Season chicken generously all over with Kosher salt and freshly ground black pepper.
Heat a drizzle of avocado oil in a large, high-sided skillet over medium-high heat. Add chicken and sear until golden, 2-3 minutes per side. Transfer to a plate.
Reduce heat to medium-low and add scallion whites, garlic, and ginger. Cook, stirring often, until softened, about 1 minute. Add coconut milk, chicken stock, soy sauce, rice vinegar, peanut butter, gochujang, brown sugar, and ½ teaspoon of Kosher salt (double this amount of salt if doubling the recipe). Stir to combine and gently scrape any browned bits from the bottom of the pan with a wooden spoon.
Bring to a boil over medium-high heat and cook until reduced by half, about 10 minutes. Then add the chicken back into the pan with any juices on the plate and turn to coat in the sauce. Bring to a simmer then turn heat to medium-low. Cook until the chicken is cooked through and sauce has thickened, about 7-9 minutes.
Remove from heat and stir juice from half a lime (double this if doubling the recipe). Taste and season with more salt, if needed. Serve sprinkled with scallion greens, cilantro leaves, and peanuts, with extra lime wedges on the side.