Thaw fish, if frozen. Rinse fish; pat dry with paper towels. Cut fish into 6 serving-size pieces. Sprinkle fish with salt and black pepper.
For sauce, in a large skillet cook onion and garlic in hot oil until onion is tender. Stir in tomatoes, olives, wine, capers, jalapeno peppers, sugar, and bay leaf. Bring to boiling. Add fish to skillet. Return to boiling; reduce heat. Cover and simmer for 6 to 10 minutes or until fish flakes easily when tested with a fork. Use a slotted spatula to carefully transfer fish from skillet to a serving platter. Cover and keep warm.
Boil sauce in skillet for 5 to 6 minutes or until reduced to about 2 cups, stirring occasionally. Discard bay leaf. Spoon sauce over fish. Sprinkle with parsley. Makes 6 servings.