Marinate the chicken with the above ingredients for about an hour and deep fry it in oil till golden brown. Do not over fry it. Keep it aside
Heat oil in a pan, add ginger garlic and saute for few seconds. To this add the diced onion and capsicum, chopped spring onion and green chili and saute on high flame for about 2- 3 minutes.
Now add the chili pwd, pepper pwd and salt and saute for a minute or two. Add the tomato ketchup, soy sauce and sugar and mix well. Add the water and let it boil.
Simmer the flame and add the corn flour paste stirring continuously. When it becomes thick add the fried chicken and mix well. Cook it on low flame for 2- 3 minutes. Serve hot.