Preheat oven to 450 degrees. Coat a baking sheet with cooking spray. Slice the zucchini into 1/4 inch thick rounds. In a medium bowl, toss zucchini with the oil. In a small bowl, combine the parmesan, breadcrumbs, salt and a few turns of pepper. Dip each round into the parmesan mixture, coating it evenly on both sides, pressing the coating on to stick, and place on a single layer onto the prepared baking sheet. Bake the zucchini rounds until browned and crisp, about 25-30 minutes. Remove with spatula, serve immediately.