1. Slice chicken breasts into thin strips. In a small bowl combine sliced chicken breasts, 2 tablespoons of olive oil, lime juice, garlic, oregano, chili powder, paprika, cumin, and season with salt and pepper to taste.
2. In a large skillet over medium high heat. Add the remaining olive oil, onion and red peppers and cook for 5 to 7 minutes or until just tender. Add chicken and cook for 5-6 minutes, stirring occasionally, or until done. Adjust the taste with more salt and black pepper if necessary. Spoon chicken mixture onto lettuce leaves and serve.