I think the primary way it encourages treasure hunting is by making treasures unique and used often. Numenera is not a game where you pick up a random belt that gives you a few bonuses which you promptly forget about as soon as you add the new numbers to your character sheet. Cyphers are great as treasures, they almost always do something impressive (at least when used smartly) and you always have a motivation to get more of them since they're all single use objects.

Artifacts are also cool when you want a step above what cyphers have to offer, but use them sparingly. Too many of them and it starts to feel like another Christmas tree. (Though it should be noted that most artifacts are necessarily permanent either, you just get more out of them than cyphers)

Oddities are weird but I like them. They are designed to be useless, acting more like art objects in D&D that happen to have little quirks to make them valuable instead of traditional treasure. However you better believe that my players tried to go out of their way to find a use for everyone they came across when I ran a game. Sure "a small neon colored plastic rod that glows in darkness" is designed to be useless (it doesn't even cast enough light to be a torch, at best it can help your friends find you in the dark) but the player still loved that she had essentially gotten a glowstick in a role-playing game and was dead set on keeping it around on the off-chance the party ever stumbled into the middle of a rave (they probably would have if that game had continued long enough).

The one thing I'm a little disappointed that they didn't include more of are discoveries. Discoveries are essentially magic locations. Devices too large or otherwise difficult to move for easy use, and more like dressing for dungeons. I was really hoping they'd have a table for generating discoveries like they did with other numenera, but it sadly was skimmed over with a more general "Make up something weird". I understand that making up your own things is likely preferable for such big setting pieces, but it would be nice for something a little more defined when you just need something weird to be in a room (besides a monster)

I suppose that is one of my biggest concerns about Numenera, as a treasure hunting game they excel at the treasure part, but the hunting is placed a little more on the GM's head. I'd really have appreciated if they made a book solely about locations (not just setting locations like the Guide to the Ninth world does. I mean something more like dungeoncrafting books that D&D makes) something to help the GM make just as weird and interesting of sites for adventures as the setting manages for their monsters and treasures. Actually one of the more counter-intuitive points in the core book I found was the encouragement to make your dungeons big and vague. Essentially doing away with strictly defined maps like in other games and instead give your players a sense of scale by saying it takes them over an hour for their characters to cross this bridge, and otherwise separating the interesting parts of the dungeon by vagaries rather than describing every room they go through. While that's all well and thematic, I feel that it runs counter to a lot of player sensibilities. If I told my player that they spend an hour going through empty corridors, they're probably going to want to roll a few dice just to make sure they didn't miss something. If I describe more, they're going to want to poke whatever it was with a stick. Even more, I fear that it encourages rail-roading by giving them the illusion of an expansive dungeon, when in reality you've only given them a few linear encounters seperated by a lot of empty "you spend a few hours searching through huge and impressive but ultimately uninteresting rooms before you arrive at the next pre-ordained encounter"

Say what you want about D&D dungeons but at least you felt like you had a clear choice when you decided to go down the left corridor instead of the right.

That said there's no reason you can't use outside sources for that sort of thing. Especially if you're using the system for a more traditionally fantasy setting. Find a better dungeoncraft book from another system, add in your own weirdness where appropriate and it's really easy to adapt things mechanically (just keep in mind that Numenera can throw expectations of environmental challenges out the window. An underwater part of a dungeon in D&D will require magical preperation or some really good swimming skills. In Numenera they can use a cypher to breathe underwater, or to evaporate the water, or phase through the walls surrounding the water. Cyphers are unpredictable and you can generally depend that PC's will be able to solve a lot of problems you throw at them with a Cypher and some creativity. (Though make sure you keep a hidden solution on standby if they accidentally hit a wall))

Some have said that the Numenera system doesn't do well with adaptation to other settings and I agree, to an extent.
The Cypher system does well with certain kinds of settings, mainly those that can handle a bit of weirdness, and can incorporate the cyphers themselves. For example I would never try to run a normal high fantasy setting like Forgotten Realms with Cypher, since this isn't a system where you can just give someone Excalibur. However I am thinking of using it to run Eberron, since it manages the low-level but ubiquitous magic feel that cyphers present. For what you're going for, Cypher was more or less already designed for (just with more blinking lights). It's not without its flaws (some things will need a little of your own work to fill in the cracks.) but it's certainly sounds like it would handle your proposed setting far better than something like an urban intrigue focused game in a distinctly low-magic setting.