Season the chicken breast evenly with half of the sea salt and black pepper.
Heat a grill pan or skillet over medium-high heat and cook the chicken for 6-7 minutes per side until the internal temperature reaches 165°F.
While the chicken cooks, dice the mango, avocado, and red onion into bite-sized pieces.
In a small bowl, whisk together the lime juice, extra virgin olive oil, and the remaining sea salt and black pepper to create the dressing.
Slice the cooked chicken into thin strips or cubes.
In a large bowl, combine the baby spinach, mango, avocado, red onion, and fresh cilantro.
Top the salad with the grilled chicken and drizzle with the lime vinaigrette before serving.