Combine all the ingredients for the Marinade (except oil) and set aside for 1/2 - 1 hour. Heat the oil in a frying pan. Deep fry the chicken pieces a few at a time. Drain when golden brown and cooked. Keep aside. In another pan, heat oil, and then add the chopped ginger, garlic and green chillies and finally some spring onion and saute for a minute. Add the soya sauce, chili sauce/tomato sauce, pepper, sugar, ajinomoto, stock and salt. Add little water and bring to a boil. Add the fried chicken and cook for 3 minutes. Then add the maida and water mixture and stir so that no lumps are formed. Cook for a few minutes until the mixture thickens slightly.