Preheat the oven to 350 degrees F.
Remove and discard the thick stems of the kale and tear the leaves into large pieces. Spread the leaves in a single layer on 2 large cookie sheets. Spray the leaves with nonstick cooking spray to coat lightly. Sprinkle with salt. Bake just until the kale chips are crisp but not browned, 12 to 15 minutes. Cool on cookie sheets on wire racks.