In a large bowl, combine onion, soy sauce, honey, ketchup, vegetable oil, garlic, ginger and red pepper.
Season chicken thighs with salt and pepper, to taste. Place chicken thighs into a 6-qt slow cooker. Add soy sauce mixture and gently toss to combine. Cover and cook on low heat for 3 hours and 30 minutes.
Remove chicken thighs from the slow cooker and shred the chicken before returning to the pot with the juices. Cover and keep warm for an additional 30 minutes.
Serve immediately, garnished with green onions and sesame seeds, if desired.
Notes
Use reduced sodium soy sauce.Reduced sodium has less sodium and less salt without compromising flavor.
Use dark or white meat. Boneless, skinless chicken breasts and thighs can be used interchangeably here but thighs are much fattier (and thus more flavorful).
Add vegetables. Mushrooms, carrots, bell peppers or snow peas can be added during the last 30 minutes of cooking time for a more heartier meal.
Serve with your favorite grains. White rice, brown rice, fried rice, cauliflower rice, quinoa or farro are all excellent options.
Freeze as needed. Once cooled completely, the leftovers can be stored in individual freezer bags, freezing up to 3 months.