Rinse the fish under cold water and pat dry. Sprinkle with 1 teaspoon salt and a few grinds of pepper. Arrange 4 fillets in a single layer in a glass or enamel pie plate. Top with half each of the scallions and ginger, then lay the remaining 4 fillets on top to make 4 sandwiches. Drizzle with 1 tablespoon soy sauce and refrigerate until ready to cook, or up to 30 minutes.
Remove the fish from the refrigerator. Fill a wok or large Dutch oven with 2 to 3 inches of water; bring to a boil. Put a large steamer in the wok (the water should not touch the bottom of the steamer). Set the pie plate in the steamer, cover and steam until the fish is cooked through, 15 to 20 minutes. Transfer the fish to a plate and drizzle with any collected juices.
Heat the peanut oil in a small skillet over medium-high heat. Add the remaining ginger, the garlic, jalapeno, sugar and 1/2 teaspoon salt and stir-fry 30 seconds. Add the remaining 1 tablespoon soy sauce and remove from the heat. Slice the remaining scallions into matchsticks and scatter over the fish along with the bell pepper. Pour the ginger mixture on top. Serve with rice.