Place the chicken thighs into the bottom of the slow cooker.
In a bowl, whisk together the pineapple juice, brown sugar, soy sauce, garlic, ginger, and ketchup until smooth.
Pour the sauce over the chicken, then add red and green bell pepper, onion, and pineapple chunks on top.
Cover and cook on LOW for 6 hours or HIGH for 3–4 hours, until the chicken is tender.
30 minutes before serving, stir in the cornstarch slurry to thicken the sauce.
Serve the chicken over rice and garnish with sesame seeds, green onions, and cilantro.