Prepare the marinade and wings: Place the 1/2 cup of hot sauce or 1/4 cup sauce and the chiles, the garlic, onion, ginger, cilantro, oil, 1/4 cup of lemon juice, and the salt and pepper in a blender and puree until smooth. Or you can puree the piripiri chiles, if using, and the garlic, onion, ginger, cilantro, salt, and pepper in a food processor, then work in the hot sauce, if using, and the oil and lemon juice. Transfer the marinade to a large nonreactive bowl or roasting pan.
Rinse the chicken wings under cold running water and blot them dry with paper towels. Cut the chicken wings in half, cutting off and discarding the tips. Add the wings to the marinade and stir to coat. Let the wings marinate in the refrigerator , covered, for at least 6 hours, or as long as overnight, stirring them every few hours. The longer the wings marinate, the richer the flavor will be.
FOR THE GLAZE:
Melt the butter in a saucepan over medium-high heat. Add the cilantro and garlic and cook until sizzling and aromatic, about 2 minutes; do not let the garlic brown . Stir in the hot sauce and lemon juice and let the glaze simmer until blended and flavorful, about 2 minutes.
Grilling the chicken wings using the direct method is truer to the way they do it at Nandos but requires a little more care than grilling them using the indirect method. Whichever method you use, drain the wings, discarding the marinade, before grilling.
If you are using the direct method, set up the grill for direct grilling and preheat it to medium. Leave one section of the grill fire-free for a safety zone. When ready to cook, brush and oil the grill grate. Arrange the chicken wings on the hot grate skin side down and grill them until crisp and golden brown and cooked through, 8 to 12 minutes per side, turning with tongs. Should any flare-ups occur, move the wings to the safety zone. If you are using the indirect method, set up the grill for indirect grilling, place a drip pan in the center, and preheat the grill to medium. When ready to cook, brush and oil the grill grate. Arrange the chicken wings skin side up in the center of the grate over the drip pan and away from the heat. Cover the grill and grill the wings until they are crisp and golden brown and cooked through, 30 to 40 minutes.
To test for doneness, make a small cut in the thickest part of one of the wings; there should be no traces of red or pink at the bone . Transfer the grilled chicken wings to a platter and pour the glaze over them. Toss to mix, then serve at once.
NOTE: You can also use 1/4 cup hot sauce plus 3 to 4 fresh piri-piri chiles, cayennes, red serranos, or other hot, fresh red chiles, stemmed and cut in half, and seeded (for hotter wings, leave the seeds in)