Wash potatoes and slice into wedges (4 to 6 wedges from each potato). Spray large piece of foil with cooking oil spray. Place potato wedges on foil. Sprinkle on onion powder, garlic salt, pepper, and paprika. Seal the foil into a package with the seam on top and sides.
Heat grill to medium high. Place foil pack on warming rack for about an hour or until potato wedges turn crispy.