In a medium bowl, whisk together all sauce ingredients until well combined. Set aside.
Place the chicken pieces into a large ziploc bag with the cornstarch; seal and shake until the chicken is evenly coated.
Heat the oil in a large skillet over medium high heat. Add the chicken and cook for 4-5 minutes, stirring occasionally, until the chicken is golden brown.
Remove the chicken from the pan and drain on paper towels.
Add the diced bell peppers and pineapple chunks (with juice) into the bottom of a 5 quart (or larger) oval slow cooker.
Place chicken into the slow cooker.Pour the mixed sauce over the top of the chicken and vegetables; stir gently and cover.
Cook on low for about 3-4 hours (or until the internal temperature of the chicken reaches 165F degrees).
Sprinkle with sesame seeds once the sweet and sour chicken has finished cooking.
Serve over cooked rice and garnish with sliced green onions.
Notes
This can also be made in the oven. Follow directions as shown below but instead of popping everything in the slow cooker, place it in a 9"x 13" baking dish and bake at 350F degrees for 45 minutes (stirring the mixture gently every 15 minutes for even coating.)
If you love a lot of sauce, feel free to double the sauce recipe.
Obviously when cooking in a crock pot, you aren't going to get crunchy chicken. This ends up being a deliciously tender, glazed chicken.