Cut meat into 2-inch cubes, discard any fat. Combine lamb with soy sauce, wine, ginger and garlic in plastic bag set into bowl. Marinate for two hours or longer in refrigerator. Reserve marinade; thread meat on skewers, alternating with mushrooms and onion leaves. Wipe gently with oil. Broil 4 inches from heat 3-4 minutes a side, basting occasionally with marinade.