Set oven to 375 degrees F.In a small bowl, combine oil, cayenne pepper, and salt (if using); stir to combine.Using clean hands, massage oil mixture into the kale leaves. Use kitchen shears, a sharp knife, or your hands to tear the leaves into bite sized pieces. Bear in mind that the chips will shrink to almost half of their original size during baking, so don't make them too small to begin with.Place chips onto a baking stone or rimmed sheet pan. Bake for 15-20 minutes, or until chips dry and slightly browned.Remove pan from oven and allow chips to cool slightly. Lightly toss chips with Parmesan cheese before serving.