Coat a baking sheet with cooking spray. In a medium bowl, toss the squash with the olive oil. In another bowl, combine the bread crumbs, parmesan cheese, dried oregano and a generous pinch of black pepper. Dip each squash round into the parmesan mixture, coating it evenly on both sides, pressing the coating on so it sticks. Gently place the squash in a single layer on the prepared baking sheet. Bake the rounds until browned and crisp, 25 to 30 minutes. Serve immediately.