How to Make It
Remove skin from swordfish. Combine swordfish and 2 1/2 teaspoons flour in a large zip-top plastic bag; seal and shake gently to coat.
Heat 1 teaspoon oil in a 10-inch cast-iron skillet over high heat. Add swordfish; cook 1 1/2 minutes on each side or until done. Remove from skillet; keep warm.
Heat 1 teaspoon oil in skillet over medium heat. Add onion; sauté 3 minutes. Add 1/2 teaspoon flour, capers, and raisins; cook 1 minute, stirring constantly. Stir in clam juice, wine, tomato paste, and water; bring to a boil. Add olives, vinegar, and sugar; cook 1 minute. Stir in parsley. Serve sauce with swordfish.