To make the chicken, whisk the coconut milk, fish sauce, curry, sugar, coriander, salt and pepper. Put the chicken in a large zip-lock bag and pour in the marinade. Seal the bag and rub the marinade into chicken. Chill for 3 hours, turning the bag occasionally.
For the sauce, combine the soy sauce, vinegar, red pepper, sugar, ginger, sesame oil, peanut butter and the stock in a pan and bring to a boil over medium heat, whisking until smooth, 2 to 3 minutes. Thin with more chicken stock, if desired. Remove from the heat, let cool, cover and chill.
Preheat the grill to medium. Remove the chicken from the marinade and discard the marinade. Thread each piece of chicken onto a metal or bamboo skewer. Grill for 5 to 7 minutes, turning once, until the chicken is cooked through and no longer pink. Serve with the sauce.