Slice sweet potatoes paper-thin and toss lightly with oil. Toss potatoes with spice mixture until evenly coated. Arrange potatoes on wire grates sprayed with nonstick vegetable spray or on baking sheets fitted with parchment paper.
Bake for 2 hours, then turn off oven and let potatoes dry for 2 more hours or overnight. Alternately, dehydrate sweet potato slices in dehydrator according to manufacturer's directions.