Place the chicken pieces in your slow cooker.
In a medium bowl, whisk together honey, soy sauce, minced garlic, ketchup, olive oil, and red pepper flakes (if using).
Pour the honey garlic sauce over the chicken and toss to coat evenly.
Cover and cook on low for 2.5 to 3 hours, or on high for 1.5 to 2 hours, until the chicken is cooked through and tender.
In a small bowl, mix cornstarch and water to create a slurry, then stir it into the slow cooker.
Cook on high for an additional 15-20 minutes, uncovered, until the sauce thickens to a beautiful glaze.
Garnish with sesame seeds and green onions, then serve with toothpicks for easy grabbing!