Place the chicken thighs in the bottom of the slow cooker insert.
Mix together the soy sauce, honey, rice vinegar, sesame oil, garlic, ginger root, onion powder, and red pepper flakes.
Pour over the chicken.
Cover and then set the slow cooker to cook on high 2-3 hours or low 4-6 hours.
Remove chicken from the slow cooker, place into a bowl, and shred.
In a small bowl mix together the cornstarch and water to create a slurry.
Pour the sauce into a sauce pan and whisk in the slurry. Cook over medium heat for about 3 -5 minutes or until the sauce thickens up. Please note the sauce will thicken as it sits.
Mix half the sauce into the chicken and put the rest on the side for extra sauce if needed.