In a glass bowl, stir together vegetable oil, lemon juice, minced onion, salt, pepper, Worcestershire sauce, bay leaf, and minced garlic.
Add steak and cover. Refrigerate overnight, turning occasionally.
Remove from refrigerator and alternate steak cubes, onions, green peppers, and tomatoes on long skewers.
Place on barbecue about 6 inches above coals and turn frequently, basting with remaining marinade until steak is cooked to desired doneness; approximately 20 minutes.