Clean and scale the fish and remove gills and innards. Rinse in running water then drain.
Make 4 diagonal slits on the fish. Season with salt and pepper and set aside in the refrigerator.
For the sweet and sour sauce, heat oil in pan and saute kinchay, red bell pepper, ginger, and lemongrass for a minute.
Add sweet chili sauce and vinegar then season with salt and pepper. Simmer for a few minutes and set aside.
Coat the fish with egg whites then coat with cornstarch. Deep fry until crispy.
Heat the sauce again then immediately glaze with simmering sweet and sour sauce.