To make the red chilli paste, grind together the soaked red chillies, garlic and cumin seeds with very little water to a fine paste.
Prepare a batter using egg whites, corn flour (half quantity), pepper and salt. Marinate the chicken pieces in this and keep refrigerated for at least 30 minutes.
Heat oil in a pan and deep fry the chicken pieces till golden brown. Drain on an absorbent paper.
Heat 2-3 tbsp oil in another pan; add the ginger, garlic and dry red chillies. Saute for 30 seconds and add the onions, chilli paste and tomato ketchup; sauté on high heat for 30 seconds.
Add soy sauce and 1 cup water. Bring to boil and add the chicken pieces. Season with salt.
Add the chopped spring onions and mix well. Mix the remaining corn flour with water and add this solution to thicken the gravy.
Add vinegar and remove from heat. Garnish with spring onions.
Serve hot with fried rice.