A276
Yes. "The caster causes a flat, vertical wall of woven, spiked chains to spring into being." It doesn't require you to be underground or near a wall.

A277
No, as the spell specifies "two daggers in your possession" that furthermore are the focus for the spell.
Quote Originally Posted by Components
A spell’s components are what you must do or possess to cast it.
That includes a focus, the daggers in this case.