Place the cubed chicken breasts in the slow cooker.
In a medium bowl, combine the soy sauce, brown sugar, honey, rice vinegar, minced garlic, and minced ginger. Stir until the brown sugar is dissolved.
Pour the sauce mixture over the chicken in the slow cooker.
Cover and cook on low for 4-5 hours or on high for 2-3 hours, until the chicken is fully cooked and tender.
In a small bowl, mix the cornstarch with the cold water to create a slurry.
About 30 minutes before serving, stir the cornstarch slurry into the slow cooker to thicken the sauce.
Cover and continue to cook on high for the remaining 30 minutes.
Once the sauce has thickened, stir well, and optionally garnish with sliced green onions and sesame seeds before serving.
