Heat peanut oil in a wok or 12-inch heavy skillet over moderately high heat until smoking. Add ginger, 1/4 cup scallions, and salt and stir-fry 1 minute. Add rice and stir-fry until beginning to brown, 7 to 10 minutes. Add remaining ingredients (including scallions) and stir-fry until liquid is absorbed, about 2 minutes. Season with pepper.