Remove tenders from chicken breasts, and slice each breast starting from the thickest point, cutting partway through until you are able to open the breast like a book. Season with salt and pepper to taste
Sprinkle half of the garlic over the opened chicken breasts. Place 2 lime wedges at the centre, and fold back the chicken to close the "book".
In a large skillet over medium-high heat, melt the olive oil. Place the chicken into the pan, add remaining garlic, pour half of the lime juice over top, and sprinkle with cumin.
Cook for 6–8 minutes, then flip chicken over. Pour the remaining lime juice over top. Cook until a nice golden sear develops on the second side, about 2–3 minutes. Then turn the heat to medium-low, and top with a lid (or use foil if you don't have a lid for your skillet) until chicken is cooked through, about 4–6 additional minutes.
Serve with mango salsa spooned over top.