Cut six 12-inch squares of foil. Place each fish fillet in center of 1 square. Drizzle each fillet with 2 teaspoons oil; turn fish to coat. Sprinkle with salt and pepper. Spread each with 2 teaspoons tapenade. Top each with 4 tomato wedges, 1/3 cup fennel, 1 teaspoon tarragon, 1 teaspoon lemon peel, and 2 teaspoons vermouth. Sprinkle with salt and pepper. Fold up foil and seal edges to enclose completely.
Prepare barbecue (medium-high heat). Place packets on grill rack; cover barbecue with lid. Cook until fish is just opaque in center, about 8 minutes. Divide packets among plates and serve.
