Food Network teaches how to crush, slice and mince garlic. Peel off some of the papery skin from the garlic and then smash the head of garlic with the heel of your hand to loosen the cloves; if you only need a few cloves, leave the head intact and pull some off. Separate the cloves. To peel a clove, cut away the root end with your knife. Lay the flat side of the knife over the clove while holding the knife handle, then with the heel of your free hand carefully whack the knife against the garlic to separate the skin from the clove. To crush the peeled garlic, lay the flat side of the knife over the clove and smash it again. To slice peeled garlic, lay the clove flat on the cutting board and hold it with the fingertips of one hand, keeping them curled under. Using a rocking motion with the knife, make thin slices by moving the knife slowly across the clove. To mince peeled garlic, lay the flat side of a knife over the clove and smash it. Roughly chop the clove then move your free hand flat across the tip of the knife and use a rocking motion to chop the garlic until it’s finely minced.
Put the mango, cilantro, lemon juice, vinegar, oil, garlic, chipotle, salt and pepper in a food processor and puree until smooth. Adjust seasonings to taste.
Add the chicken with half of the chipotle-mango sauce to a resealable plastic bag, and massage to coat the chicken with the sauce. Refrigerate at least 6 hours to marinate.
Put the other half of the chipotle-mango sauce into a small saucepan and simmer over low heat until thick, stirring often, about 15 minutes. Set some of the simmered sauce aside to serve on the side, and baste the chicken every few minutes with the rest of the sauce.
Preheat a grill or grill pan to medium-high heat and brush with oil. Remove the chicken from the marinade and put on the grill.
Grill the chicken, turning and basting about every 5 minutes, until cooked through, 20 to 25 minutes. Transfer to a serving platter and serve with the reserved chipotle-mango sauce.