Over high heat, start heating the cooking oil in a wok or frying pan.
Wipe the fish fillets dry with paper towels. Cut into serving size pieces. Sprinkle liberally with salt and pepper on both sides.
Whisk the flour and starch together. Pour in enough ice-cold water to make a fairly thin batter (the ideal consistency is thinner than pancake batter).
Dip each piece of fish fillet in the flour-starch mixture to cover completely.
When the oil is hot (you should see fine wisps of smoke float on the surface), drop in the battered fish fillets. Cook in batches if necessary so as not to overcrowd the pan and make the temperature drop. Depending on the thickness of the fillets, cook for three to five minutes or until the batter has turn crisp and lightly browned and the fish is cooked all the way through. For even cooking, flip the fish fillet midway through the frying.
Arrange the fish fillets on a plate. Pour corn sauce over them. Optionally, you may garnish your Chinese-style fish fillet with sticky corn sauce with sliced scallions before serving.