Add water to a medium pot, fitted with a steamer insert, and bring to a boil.
Coat a large wok heavily with 2 tablespoons grapeseed oil and heat until the oil is almost smoking. Meanwhile, season the eggs with salt and pepper. Add the eggs to the heated oil and stir vigorously until puffed and cooked through, about 2 minutes. Remove from the wok and set aside in a bowl. To the same wok, add another 2 tablespoons grapeseed oil and heat until hot, then add the garlic, 2 tablespoons scallions and 1 tablespoon ginger and saute for 1 minute. Add the rice and eggs back in, mixing gently. Season with the tamari and sesame oil. Mix well to combine. Remove from the heat and let cool slightly.
Lay a banana leaf on your work surface. Place about 1/4 cup cooled rice in the middle. Sprinkle a piece of fish on both sides with salt and pepper and place on top of the rice. Top with a few Thai basil sprigs. Fold the banana leaf and wrap tightly, similar to wrapping a sandwich in foil or plastic wrap. Repeat with the remaining fish. Carefully place each piece of wrapped fish in a steamer insert, seam-side down. Add the tea leaves to the simmering water and set the filled steamer insert over the water and cover. Steam until the fish is cooked through, about 12 minutes.
Meanwhile, when is the fish has about 3 minutes left, heat the olive oil in a small saucepan.
Cut the fish packets open with scissors, then top each pieces of fish with the remaining 2 tablespoons scallions and tablespoon ginger. Spoon the hot olive oil over the top of each piece of fish and serve.