In a medium container, mix Worcestershire sauce and mustard. Place steak strips in the mixture. Cover, and marinate in the refrigerator at least 30 minutes.
Place rice and water in a medium saucepan, and bring to a boil. Reduce heat, cover, and cook 20 minutes.
Heat olive oil in a medium saucepan over medium heat. Stir in the onion and garlic, and cook until tender. Season with pepper. Place steak into the saucepan and cook 5 to 7 minutes on each side, to desired doneness. Discard remaining marinade. Serve over the cooked rice.