Slice the persimmons as thinly as possible. Arrange the persimmons on the baking sheet in a single layer and lightly sprinkle each side with cinnamon (a little goes a long way). Bake for 10 minutes until slightly dried and the ends have started to curl. Flip the persimmons over and bake for another 5-10 minutes until the persimmons are dried. Allow to cool slightly before serving.