Combine 3/4 cup picante sauce, oil, vinegar, oregano and garlic; mix well.
Place beef in zip-style bag; pour marinade mixture into bag. Seal and chill 2 hours to overnight.
Remove meat from bag, discard marinade. Grill steak over medium-high heat to desired doneness. Slice into thin strips. (**To substitute the fully cooked beef strips or shredded beef, heat according to package directions and continue as below.)
Meanwhile, divide evenly between tortilla bowls the lettuce, tomato, green onion, black olives, and black beans. Top with grilled steak strips.
Sprinkle top with grated cheese and serve with Ranch Dressing and remaining picante on the side.
SOURCE: The Texas Beef Council