Makes 4 servings
Hands-on time: 15 minutes
Total preparation time: 30 minutes plus marinating time

For the adobo:
2 guajillo chilies, wiped clean, stemmed, seeded and toasted very lightly
2 chiles de arbol (with seeds) or less, depending on heat, wiped clean and well toasted
3 large garlic cloves
1/2 teaspoon cumin seeds
1/8 teaspoon ground cloves
1/2 teaspoon dried oregano, crumbled
1 tablespoon cider vinegar
1 pound boneless, skinless chicken breasts
Salt

Prepare the adobo: Put both chiles, the garlic, cumin, cloves, oregano, water, and vinegar in a blender jar and blend at low speed until smooth.

Pound the chicken with a meat mallet to an even thickness of about 1/4 inch. Rub the adobo over the chicken and (wearing gloves, if you like) rub the marinade into the chicken. Cover and let stand at room temperature for up to 1 hour, or refrigerate for up to 1 day. Bring to room temperature if necessary before continuing.

Heat a gas grill to medium-high or prepare a hot charcoal fire. Grill the chicken, turning once, until charred in places and cooked through, about 10 minutes. Remove to a carving board, cover with foil, and let stand for 5 minutes before slicing and serving.