Thaw fish, if frozen. Remove any skin; cut fish into six 1/2-inch-thick portions. Sprinkle fish with white pepper.
Combine the wine, water, coriander seed, star anise or anise seed, and lemon slices in a large skillet. Bring to boiling. Reduce heat to simmering. Carefully place the fish fillets in a single layer in the bottom of the skillet; cover and simmer for 4 to 6 minutes for each 1/2 inch of thickness or until fish just flakes when tested with a fork. Carefully remove fish fillets with a slotted spatula. Cover and chill for 2 hours or overnight.
In a small mixing bowl combine sour cream, dill, and lime juice. Add salt and pepper to taste. Cover and chill for 1 hour or until serving time.
Arrange lettuce on six dinner plates. Top with fish fillets. Spoon Dilled Sour Cream over each serving. Garnish with fresh dill, if desired, and cucumber slices. Makes 6 servings.