Prep: 12 minutes
1. Combine 1/4 cup sour cream and adobo sauce in a small bowl, stirring well. Place 1 tortilla on each of 4 plates. Spread 1 tablespoon sour cream mixture over each tortilla. Top each evenly with salad greens; arrange beef over greens.
2. Combine tomato, pepper rings, and avocado in a medium bowl; toss gently. Top beef evenly with tomato mixture.