In a large mixing bowl, combine peanut butter, coriander, salsa, sugar, soy sauce, salt, lemon juice, cayenne pepper, black pepper, garlic and spring onions. Mix well. Add chicken, cover and refrigerate for at least 4 hours.
While the chicken is marinating, soak bamboo skewers in water for one hour so they will not burn on the barbecue.
Preheat the barbecue to a high heat or preheat the griller.
Thread chicken alternately with capsicum onto skewers. Barbecue turning once, for 4 to 6 minutes or grill until browned and cooked through.