Add the chicken cubes, cornstarch, and freshly cracked black pepper to a plastic ziptop bag. Shake the bag until the chicken is coated in the cornstarch.
Heat the oil in a large pan (I prefer a non-stick pan) over high heat. Add the chicken and sear it until it is well browned on all sides, about 10 minutes. You may need to do this in batches depending on how large your pan is. Avoid crowding the pan. This is steam the chicken instead of searing it.
Add the chicken to the slow cooker. In a bowl whisk together the hoisin, soy, honey, vinegar, garlic, ginger, and red pepper. Pour mixture over the chicken in your slow cooker.
Set your crockpot to low for 2 hours. Check the chicken after 2 hours. Cook another hour is needed. You can easily double or triple this recipe. However, it may take longer to cook if you do.
Serve plain, over rice, quinoa, or vegetables sprinkle of green onions on top.