Mix soya chunks, salt, two teaspoons cornflour, green chilli paste and dark soy sauce in a bowl. Heat half the oil in a pan, add the soya chunks and sauté for two to three minutes. Transfer into a bowl. Add the remaining oil to the same pan and sauté onions, spring onions, ginger and garlic for two to three minutes.
Add soy sauce, green chilli sauce and tomato ketchup and mix. Add two cups of water and let the mixture come to a boil. Add the soya chunks and cook for five more minutes. Add salt and mix. Add remaining cornflour dissolved in two tablespoons of water and cook till the mixture thickens slightly. Add capsicum, stir in vinegar and take it off the heat. Garnish with spring onion greens and serve hot with fried rice or noodles.