Braised Fish Hunan-Szechwan Style

1 sea bass, gray mullet or trout, about 1 pound 6 ounces to 1 pound 8 ounces, cleaned, with head left on
1/2 teaspoon salt
8 ounces peanut or corn oil
3 or 4 cloves garlic, peeled and chopped fine
1 inch fresh ginger root, peeled and chopped fine
2 to 4 tablespoons Szechwan chili paste or hot soybean paste
1 tablespoon Shaohsing wine or medium-dry sherry
1/2 teaspoon sugar
4 ounces clear stock or water
1 tablespoon hot chili oil
6 to 8 scallions, green parts only, cut into small rounds

Blot the fish dry. Rub salt all over it, including the cavity. Let stand for about 15 minutes. Heat a wok over high heat until smoke rises. Pour in the oil. Tip the wok carefully to swirl it all around the sloping edges. Pour all but 2 tablespoons into a container. Lower the heat. Add the fish at once and brown for about 2 minutes. Slip 2 metal spatulas underneath the fish and turn over carefully. Brown the other side for about 2 minutes. Transfer to a plate. Turn up the heat. Add another 2 tablespoons of oil to the wok and heat until smoke rises. Now add the garlic and ginger and, as they sizzle, add the Szechwan chili or hot soybean paste, wine or sherry and sugar. Pour in the stock or water and bring to a boil, stirring to mix. Return the fish to the wok, lower the heat, cover and simmer in the sauce for 12 to 15 minutes. Turn the fish over carefully and simmer, covered, for another 12 to 15 minutes, until the fish is cooked and some of the sauce has been absorbed. Remove the cover. Turn up the heat to reduce the sauce, spooning it over the fish continually. Transfer only the fish to a warm serving plate. Add the hot chili oil to the sauce, then the scallions. Stir and cook for a few seconds, then scoop the sauce over the fish. Serve immediately.