Preheat the oven to 430°F. Grease a baking dish (unless it is non-stick).
Wash and scrub the radishes. Peel them with a vegetable peeler, leaving half of the peel in stripes if desired. Slice the radishes thinly - very thin slices will be more chip-like, slightly thicker slices will be moister - and put the slices in the baking dish.
Pour a little olive oil, a little vinegar, sprinkle salt and pepper. Toss with a wooden spoon to coat. Pour and sprinkle more if necessary, until all the slices look comfortably dressed - but not drenched.
Put in the oven to bake for about 40 minutes, until the chips are golden and their edges start to crisp up. Serve warm, as an appetizer or a side.