On the cake challenges on Food Network, what is that spray can they use? I'm thinking it's air, like you use to clean computer keys, and it gets cold.
Does this cold make things set up faster?

Yes it's used to help chocolate sugar and other things set quickly, especially when being used to glue structural elements. You should get some that is designed for culinary work (check out chefrubber.com) because the propellants used in the office store variety may not be safe for working on food.