Take a wok and heat oil. Add chicken and saute it at high flame for 5-10 min.Sprinkle red chili powder and mix it well.Add vinegar and give a good stir.Once it’s almost done add sliced garlic and tomato sauce, cook for 2 min.Add chopped spring onion ,1 tsp black pepper powder and saute again for 2 min at high flame.Adjust salt.