Add the trimmed chicken breasts to the base of a 6-8 quart slow cooker basin.
To a small bowl, whisk together the garlic, ginger, honey, brown sugar, soy sauce, sesame oil, and rice vinegar.
Pour the sauce over the chicken.
Cover and cook on LOW for 5-6 hours or HIGH for 3-4 hours.
Once cooked, remove the chicken from the slow cooker and shred with two forks and set aside. Pour the sauce from the slow cooker into a medium saucepan.
Move the saucepan to the stove over medium-high heat and bring to a simmer.
To a small bowl, add the cornstarch and cold water and mix together until dissolved.
Pour the cornstarch mixture into the saucepan and bring it to a low boil. Cook for 1-2 minutes or until the sauce has just thickened.
Place the shredded chicken back into the slow cooker and pour the thickened sauce over the top. Stir to distribute.
Serve over rice topping with sesame seeds and scallions.