Start by marinating the chicken. In a small bowl, mix olive oil, orange juice, cumin, salt, and pepper. Coat the chicken breast in this mixture and let it marinate for at least 15 minutes.
Heat a skillet over medium heat. Add the marinated chicken and cook for 6-7 minutes on each side or until fully cooked through, and the internal temperature reaches 75°C (165°F). Remove from heat and let rest for 5 minutes before slicing.
While the chicken is cooking, prepare the salad base. In a large mixing bowl, combine baby spinach, romaine lettuce, and the sliced bell peppers. Toss gently to mix.
Slice the cooked chicken and place it on top of the salad. Drizzle the remaining dressing over the salad and toss lightly.
Garnish with fresh mint leaves and serve alongside a spoonful of yogurt on the side. Enjoy immediately!