Trim fat from steaks. Place each steak between 2 sheets of heavy-duty plastic wrap; flatten each piece to 1/4-inch thickness using a meat mallet or rolling pin. Rub steaks with garlic. Lightly spoon flour into a dry measuring cup, and level with a knife. Combine flour, salt, and pepper. Sprinkle the steaks with the flour mixture.
Heat oil in a large cast-iron skillet over medium-high heat. Add steaks, and cook for 4 minutes or until brown. Turn steaks over. Add onion, and cook 4 minutes. Add water. Cover, reduce heat, and simmer for 1 1/2 hours or until meat is tender.