Place chicken thighs in the slow cooker.
In a bowl, whisk together honey, soy sauce, ketchup, hoisin sauce, garlic, rice vinegar, ginger, and red pepper flakes.
Pour the sauce over the chicken and stir to coat.
Cover and cook on low for 4 hours or high for 2 hours until the chicken is tender.
Remove chicken, shred it with two forks, and return it to the slow cooker.
Stir in the cornstarch slurry and cook for another 15 minutes until the sauce thickens.
Garnish with sesame seeds and sliced green onions before serving.