Take the chicken pieces in a bowl. Add vinegar, salt, water, ginger-garlic paste, oil and coarse black pepper powder. Now mix well and set aside for at least 2 hours.
Now add the cornflour and refined flour/maida. Mix well
Heat oil in a pan for deep frying. Wait for the oil to completely hot. Now add chicken pieces one by one. Fry these in medium flame. Do not over fry the chicken or it will turn hard.
Take a small bowl add soya sauce, chili garlic sauce, and sugar. Mix well.
Heat oil in another pan. Add chopped garlic and chopped ginger. Fry for some seconds.
Then add chopped spring onion, diced onion, slit green chili, and diced green bell pepper.
Add salt. Remember not to add too much of salt as the sauces have salt in them.
Fry for 2 minutes on high flame.Lower the flame and add the cornflour and water mixture. Stir for some seconds.
Now add sauces mixture. Mix well and turn off the flame and wait for a minute. This step is needed just to maintain the crispiness of the chicken.
Now add chicken pieces and coarse black pepper powder and mix well. Sprinkle some chopped green spring onion ends. Then serve hot.