How to Make It
Add chicken, bell pepper, chicken stock, onion, carrots, soy sauce, Worcestershire sauce, sambal oelek, and 1/2 cup ketchup to a 6-quart slow cooker. Cover and cook on low until chicken shreds easily with a fork, about 7 hours. Remove chicken from slow cooker. Shred chicken, and cover to keep warm.
Whisk together pineapple juice and cornstarch in a small bowl. Increase slow cooker heat to high; slowly stir in pineapple juice mixture and remaining 1/4 cup ketchup. Cook, uncovered, until sauce is thick enough to coat the back of a spoon, about 30 minutes. Stir in chicken. Serve over rice, and sprinkle with sesame seeds and scallions.