01 - Place chicken thighs or breasts in the bottom of the slow cooker.
02 - Whisk together soy sauce, honey, ketchup, rice vinegar, sesame oil, garlic, ginger, and red pepper flakes in a medium bowl until well combined.
03 - Pour sauce over chicken, ensuring all pieces are evenly coated.
04 - Cover and cook on LOW for 4 hours or HIGH for 2 hours, until chicken is tender and cooked through.
05 - Remove chicken from slow cooker and shred or cut into bite-sized pieces. Set aside.
06 - Mix cornstarch and water in a small bowl to form a slurry. Stir into sauce in slow cooker.
07 - Return chicken to slow cooker, stir to coat, and cook on HIGH for 20-30 minutes until sauce thickens.
08 - Serve hot, garnished with sesame seeds and sliced green onions. Pairs excellently with steamed rice or stir-fried vegetables.