Marinate the chicken pieces in the yogurt, soya, ginger and a little salt. Leave aside for a minimum of 1/2 an hour or upto 2 hrs. Deep fry these chicken pieces till light brown in colour. Keep aside. In the same oil fry the capsicum and spring onions. Keep aside.
In a separate kadai, take a little oil -add garlic and green chillies. Then add the fried chicken, salt, sugar, soya sauce and cook for 5 mins.
Add 1/4 cup water, add tomato puree and at the end, add corn-starch paste and pepper powder. Mix and let cook for 5-10 mins. Serve hot with Chinese fried rice.