Try this bright idea!
Place racks in the top and bottom thirds of the oven; preheat to 200°. Line 2 baking sheets with foil; mist with cooking spray. Using a serrated knife or a mandoline, slice citrus very thinly. Place the citrus on the pans, 3 inches apart; sprinkle with superfine sugar. Bake, periodically rotating the baking sheets, until the slices are dry, 2 to 2 1/2 hours. Watch closely during the last hour to be sure that the slices don’t burn.
More delicious citrus recipes:
Fancy Cranberry Sauce with Candied Orange Peel