Heat oil in a large saucepan over medium heat. Add onions and sauté for 2 minutes. Add ground beef and sauté for 3 minutes, stirring to break up meat into small pieces. Add tomatoes, garlic, chili powder, cumin, and oregano. Reduce heat to low and simmer for about 20 minutes. Add potatoes and season with salt and pepper. Remove from heat and let mixture come to room temperature. Lay torn pieces of Manoa lettuce on 4 individual plates. Top with beef mixture and drizzle with Avocado Vinaigrette. Serves 4.
Approximate Nutrient Analysis per serving (based on 4 Tablespoon drizzled vinaigrette per serving and not including salt to taste; sodium will vary depending on amount of salt added to vinaigrette):
660 calories, 55 g fat, 11 g saturated fat, 80 mg cholesterol, 350-500 mg sodium, 20 g carbohydrate, 7 g fiber, 4 g sugar, 24 g protein