Trim fat from ribs. Cut ribs into 4-6 serving size pieces.
Arrange medium hot coals above a charcoal pan. Place ribs bone side down, on rack above drip pan. Cover and grill for 1 to 1¾ hours or until tender.
Meanwhile, for sauce, in a small saucepan gradually stir hot water into peanut butter (mixture will stiffen at first).
Stir in lime juice, green onion, ginger, and red pepper.
Cook and stir over low heat until heated through. Spoon sauce over ribs.