Begin by lightly seasoning your boneless skinless chicken thighs or breasts with salt and black pepper on both sides.

In a medium mixing bowl, whisk together the honey, soy sauce, ketchup, minced garlic, grated ginger, rice vinegar, and red pepper flakes.

Place the seasoned chicken pieces in your slow cooker, and pour the prepared sauce over the chicken, ensuring each piece is well coated.

Cover the slow cooker and set it to cook on low for 4-5 hours or on high for 2-3 hours.

If you prefer a thicker sauce, remove the chicken once it's cooked and mix cornstarch with water to create a slurry, then stir it into the remaining sauce.

Return the chicken to the slow cooker, garnish with sesame seeds and sliced green onions, and serve with steamed rice or noodles.