Heat one tbs oil in a pan. Add the duck pieces. Stir it well . Sauté till water from the duck pieces dries up. Remove from the fire and keep aside. Heat one tbs oil in the pan and add sliced onions and green chilies. Sauté till light brown. Add curry leaves, ginger & garlic paste chili powder, coriander powder , turmeric powder, masala powder and fry till brown. Add the fried duck pieces, one cup water, salt, pepper and vinegar. Cover and cook till done. Remove lid and simmer till dry.