Pick the leaves and tender stems from 8 fresh cilantro sprigs and reserve for serving. Finely chop the remaining stalks and place in a medium bowl.
Stir in ⅔ cup full-fat coconut milk, 3 tablespoons lime juice, 2 tablespoons peeled and finely grated ginger, 2 tablespoons honey, 2 tablespoons sambal oelek if using, 2 finely grated garlic cloves, ½ teaspoon of the kosher salt, ¼ teaspoon ground turmeric, and ¼ teaspoon black pepper. Transfer ⅓ cup to a small bowl.
Toss 2 pounds boneless, skinless chicken thighs, 1 tablespoon neutral oil, and the remaining ½ teaspoon kosher salt together in a separate medium bowl.
Heat a large cast-iron skillet or grill pan over medium-high heat until very hot when you hover your hand over the pan. Add the chicken in a single layer and cook until golden brown and cooked through, about 5 minutes per side.
Brush the chicken with some of the reserved ⅓ cup sauce. Cook, flipping the chicken and basting frequently with the sauce, until charred in spots and shiny, 1 to 2 minutes more.
Transfer the chicken to the bowl of remaining coconut sauce and toss to coat. Transfer to a serving platter and spoon some of the sauce over. Top with the cilantro leaves and tender stems, 2 thinly sliced medium scallions, and ¼ cup crushed roasted, salted peanuts. Serve with lime wedges.
