01 - Place the chicken thighs or breasts in the bottom of the slow cooker, ensuring even distribution for consistent cooking.
02 - In a medium bowl, whisk together the pineapple juice, soy sauce, brown sugar, ketchup, rice vinegar, minced garlic, and grated ginger until the sugar dissolves completely.
03 - Pour the prepared sauce evenly over the chicken pieces, coating them thoroughly for maximum flavor absorption during cooking.
04 - Scatter the sliced onion, red and yellow bell pepper pieces, and pineapple chunks over the chicken and sauce mixture.
05 - Cover and cook on LOW setting for 4-5 hours, or until the chicken reaches an internal temperature of 165°F and becomes tender enough to shred easily.
06 - Remove the cooked chicken and vegetables to a serving platter, covering loosely with foil to maintain warmth while finishing the sauce.
07 - In a small bowl, mix the cornstarch and water with a fork until smooth and lump-free, creating a slurry for thickening.
08 - Transfer the cooking liquid from the slow cooker to a saucepan. Bring to a simmer over medium heat, then whisk in the cornstarch slurry. Cook for 2-3 minutes while stirring constantly until the sauce reaches desired consistency.
09 - Pour the thickened sauce over the chicken and vegetables. Garnish with sliced green onions and sesame seeds if desired. Serve immediately over steamed white or coconut rice.