Cut the sea bass into 4 to 5 pieces and wipe dry with paper towels. Place in a glass baking dish.
To prepare marinade, combine 1 teaspoon salt, the ginger, vegetable oil, pepper and soy sauce in a small bowl. Rub the marinade on all sides of the fish. Cover and marinate for 30 minutes (but no more than 2 hours) in the refrigerator.
Heat oven to 500 degrees F.
Slice the cucumber very thinly. Blend vinegar, sugar, sesame oil and remaining 1/2 teaspoon salt in medium-size bowl. Add the cucumber; toss. Let soak for 10 minutes. Discard excess dressing. Place cucumber slices in a overlapping pattern around edge of a serving platter.
Line the inside surface of a large Dutch oven or ovenproof wok completely with heavy foil. In the foil-lined pan (see note), mix together the tea leaves, brown sugar and rice; spread out evenly over bottom. Place a metal steam rack on the tea leaves; the rack should stand at least 1 inch above the leaves. Place the marinated fish on the rack. Cover the pan tightly. (The tea leaves and brown sugar will smoke the fish, so be sure the pan is tightly covered. If the cover doesnt fit tightly enough, place foil around the outside of the cover and pan.)
Place in 500 degree F oven for 15 minutes. Remove from the oven and let stand, covered, for 5 minutes. Carefully open the lid. Using a spatula, carefully transfer the fish to platter. Makes 4 servings.
If you use too heavy a pan, you will not get enough heat in the oven to brown the sugar and produce the smoky flavor.