Mix all ingredients (except sauce) with meat and reserve for 4 hours.
Skewer meat pieces on bamboo sticks or skewers and grill until tender.
To make sauce: Heat 3 tbsp oil. Fry onions, garlic and ginger. Add all other ingredients and cook till blended, adding half to 1 cup of water as needed.
Serve the kebabs hot with this sauce and onion rings.