In a large bowl, mix together the chicken, curry powder, 2 teaspoons red curry paste, sugar, salt, and 1/4 cup of the coconut milk. Marinate for 20 minutes or longer.
Thread the chicken onto the skewers. If using wooden skewers, be sure to soak them in water in advance.
Heat a large skillet over medium heat. Add the oil. When hot, cook the skewers, in batches, if needed, for 3 minutes per side.
In a saucepan over medium heat, combine the rest of the coconut milk, peanut butter, apple cider vinegar, sweet soy sauce, brown sugar, red curry paste and salt. Whisk until smooth then simmer for 5 minutes.Thin with water, if necessary for the right consistency.
When chicken is done, stack it on a serving platter and garnish with your choice of peanuts, lime wedges, cilantro, and red chilis.
Pour sauce into a bowl. Sprinkle with peanuts.
Serve with the sauce on the side.