Slice the radishes as thin as possible (the thinner the slices, the crispier the radish chips will be).
Put the radish slices on a large sheet of paper towel in a single layer, then cover with another sheet of paper towel. Press on the paper towel with your hands over the radish slices to draw the moisture out.
Put the radish slices in a bowl and toss with olive oil.
Put the radish slices on the baking sheets in a single layer, so they are not touching.
Put the baking sheets in the oven and bake for 2 hours (or until radish chips are crisp).
Remove the radish chips from the oven and sprinkle with salt and pepper to taste.