Preheat oven to 200°. In a large bowl, toss apples with sugar and cinnamon.
Place a metal rack inside a rimmed baking sheet. Lay apples slices on top of rack, spacing them so that no apples overlap.
Bake for 2 to 3 hours, flipping apples halfway through, until apples dried out but still pliable. (Apples will continue to crisp while cooling.)