That's probably going to be quite difficult to do, but here is some general advice.
Because the model will need to fold along two different directions you can't just use one skincluster, you'll need to create several duplicates of the geometry each with their own skinCluster. You'll want to make sure that each fold is done with a subtle bend so that the two faces of the paper don't just completely overlap.
If I have time to look into it more in detail I'll add to this thread.
