In a big mixing bowl mix cornflour, flour, Kashmiri chilli powder and salt. Add cubed paneer pieces and toss.
Sprinkle few drops of water and mix gently by hand to coat the paneer. The mixture should just stick to the paneer.
In a wok of flat skillet add 2-3 tablespoons of oil. Once hot, arrange paneer cubes in a single layer. Keeping it apart preventing them sticking to each other. if the pan is small, shallow fry paneer in 2 batches.
Cook undisturbed for 2-3 minutes in medium-high heat. Then flip and cook until it is golden from all the sides.
Remove fried paneer cubes, drain excess oil and keep in plate.
To the same pan/wok add another 1 tablespoon of oil. When hot, add dry red chilli, green chilli, minced ginger and garlic. Saute for a minute until everything is aromatic.
Add in cubed onion and capsicum. Stir fry on high heat for about a minute.
Add fried cubed paneer pieces and prepared sauce. Toss on high heat for about 2 minutes until the sauce has thicken and sticks to the paneer cubes.
Garnish with spring onion while serving.