A70: The general rules are in two places: The Acrobatics skill, and the terrain rules. If the surface is greater than 3ft. wide, the base DC is 0, and then you start adding on the modifiers for slipperiness, your own speed, whether you're moving past an opponent etc. The terrain rules are what let you know that just about anything can make a surface slippery, including water or blood.

The rules for actually coating a surface with a substance, I'm having a bit more trouble finding, but that one might be judgmental anyway - you could say for example that a lantern or vial of oil should coat a 5ft square, but what about a bucket? That may need a ruling.