With a vegetable peeler or a mandoline, thickly peel the carrots lengthwise to make "ribbons". Place ribbons in a bowl and spray with cooking spray. Add salt and cumin and toss. Place parchment paper on 2 cookie sheets and lightly spray with cooking spray. Place carrots on the sheets, in 1 layer, and bake for 10 minutes. Remove from oven and turn over and bake until crispy, another 5 to 10 minutes.