To prepare the fish, make shallow crosswise cuts on both sides of the belt fish without cutting all the way through. In a bowl, add the fish with the ginger, scallions, rice wine, salt, and white pepper, then mix and let it sit for about 10 minutes. Remove the aromatics and liquid, then coat the fish lightly with cornstarch.
To make the sauce, in a bowl, mix together the chicken stock, soy sauce, dark soy sauce, oyster sauce, vinegar, and sugar.
To cook the fish, in a pan over medium-high heat, add the cooking oil. Place the fish in and let it cook until golden on both sides, about 3 minutes total.
To build the flavor, remove most of the oil, leaving a thin layer. Add the minced ginger and garlic, then stir-fry briefly until fragrant.
To braise the fish, pour in the sauce, cover, and let it simmer over medium-low heat for about 4 minutes.
To finish, uncover and raise the heat to high. Let the sauce reduce slightly until it coats the fish. Add the scallions and chili, then serve.