Preheat oven to 225° F. Line a baking sheet with parchment paper or nonstick foil, then spray with cooking spray.
Slice zucchini into thin medallions, about the thickness of a quarter. (You can either use a knife & a very steady hand, or a mandolin slicer.)
Lay out slices in a single layer on the prepared baking sheet, then spray tops lightly with additional cooking spray.
Sprinkle with seasonings of your choice. (A note on seasoning: use LESS than what seems appropriate. These shrink considerably in the oven, and if you use too much it gets very concentrated. It would be better to under-season and add more after baking).
Place in preheated oven and bake for 45 minutes; rotate baking sheet, then bake for an additional 30-45 minutes, until chips are browned and crisped to your liking.
Serve immediately if possible, within a couple of hours for best results.