In a medium bowl, whisk together 0.25 cups aji amarillo paste, 3 tablespoons lime juice, 2 tablespoons red wine vinegar and 0.25 cups extra-virgin olive oil until emulsified.

Add 4 tablespoons minced garlic, 0.5 cup finely chopped cilantro, 0.25 cup finely chopped parsley, 1 teaspoon ground cumin, 1 teaspoon smoked paprika, 1 tablespoon brown sugar, 1.5 teaspoons sea salt, 1 teaspoon freshly ground black pepper and (optional) 1 teaspoon hot sauce. Stir thoroughly to combine so the sugar and salt dissolve and herbs are evenly distributed.

Taste the marinade and adjust seasoning: add a little more lime for brightness, a pinch more salt for depth, or extra hot sauce for heat. The final marinade should be tangy, aromatic and slightly spicy.

Chicken

Prep chicken

Pat 8 bone-in, skin-on chicken thighs dry with paper towels. Trim any excess fat or loose skin. Using a small knife, make 2 shallow cuts through the skin and slightly into the flesh on the thickest part of each thigh so the marinade penetrates.

Marinate

Place the thighs in a large zip-top bag or a shallow nonreactive dish. Pour all of the prepared aji marinade over the chicken, making sure each piece is well coated. Massage marinade into the cuts and under the skin where possible. Seal the bag or cover the dish and refrigerate for at least 3 hours, preferably 8–12 hours for maximum flavor. If short on time, marinate at room temperature for 45–60 minutes.

Bring to temperature

Remove the chicken from the refrigerator 30 minutes before grilling to take the chill off; this promotes even cooking.

Preheat grill

Prepare a two-zone fire on a gas or charcoal grill: one side medium-high (about 400–450°F / 200–230°C) for searing, the other side medium-low (about 300–325°F / 150–160°C) for finishing. Oil the grates lightly with 2 tablespoons neutral oil on a folded paper towel held with tongs to prevent sticking.

Grill — sear

Place thighs skin-side down over the medium-high zone. Sear without moving for 4–5 minutes until the skin is deeply golden and crisp, monitoring for flare-ups; move briefly to cooler zone if excessive charring occurs.

Grill — finish

Flip the thighs and move them to the medium-low zone. Close the lid and continue cooking until the internal temperature reaches 165°F (74°C) in the thickest part away from bone, about 12–18 minutes depending on size. Turn once halfway through for even browning. If using a thermometer, insert from the side avoiding bone.

Rest

Transfer the chicken to a clean tray and tent loosely with foil. Let rest 5–8 minutes so juices redistribute.

Finish & Garnish

Sprinkle 0.25 cup fresh cilantro leaves over the rested thighs and finish with a light pinch (about 0.5 teaspoon) of coarse sea salt if desired.

Serve each thigh with lime wedges (4 pieces) to squeeze over the chicken for brightness. Recommend serving immediately while hot.