Toss kohlrabi with olive oil. Season with salt. Arrange in a single layer on a baking sheet lined with a nonstick mat. Bake at 250 degrees, rotating sheet, until crisp and deep golden, 35 minutes to 1 hour; transfer chips as they're done to a paper-towel-lined plate. Season with salt.
Look for kohlrabi with unblemished leaves and a bulb that's 3 to 4 inches in diameter; the bulb should not appear cracked or overgrown.