Prepare rub by combining chili powder, paprika and salt in a small bowl. Toss with potatoes. Arrange in a single layer on one or two parchment-lined baking sheets. Roast in a preheated 425°F (220°C) oven for 20 to 25 minutes or until browned on the bottom. Turn potatoes over and roast 10 to 15 minutes longer, until tender, crisp and nicely browned.