If you want to use Unity, I think that you could get away with simply changing the Material of the Hand models.
If this is a good idea, then you would need to learn how to properly capture the textures of your physical gloves and recreate them virtually. Then it would be a matter of changing textures on the materials. This is assuming thin leather type gloves that could be represented as skin. If your gloves are more like ski or snowboarding, then you would need to look into creating the model of the glove and binding it somehow to the hand.
I'm no expert in Leap or Unity but I figured I would chip in.