Heat a nonstick pan with a tsp oil, Add the finely chopped onions from the spring onions, then add finely chopped garlic. Sauté till the onion bulbs turn color. Keep the green of the spring onions for latter use.
Next add the remaining ginger garlic and chilli paste. Add soya sauce. Followed by tomato sauce.
In a small bowl mix the corn flour with little water to form a smooth paste. Once the sauce simmering is cooked, add the corn flour paste. Cook on high flame so that the sauce thickens. Just make sure it doesn't become too thick. Add water as required and bring to boil.
Add fried vegetable balls to the sauce, along the green onions stalks, simmer for a minute.
If you don't want the manchurian to be soggy, add just before serving.