In a medium bowl, whisk together soy sauce, honey, brown sugar, garlic, ginger, rice vinegar, sesame oil, red pepper flakes (if using), and 1/4 cup water.
Pour the sauce over the chicken in the crock pot.
Cover and cook on low for 4-5 hours or high for 2-3 hours, until the chicken is tender and easily shredded.
Remove the chicken from the crock pot and shred it using two forks.
In a small bowl, mix the cornstarch with 2 tbsp cold water to create a slurry.
Pour the slurry into the sauce in the crock pot and stir well.
Turn the crock pot to high and let the sauce thicken for about 10 minutes.
Return the shredded chicken to the crock pot and stir to coat in the sauce.
Serve over rice or noodles, garnished with green onions and sesame seeds.
Notes
Feel free to adjust the sweetness by modifying the amount of honey and brown sugar.
This recipe can also be made with chicken breasts, but thighs tend to be juicier.