Place the chicken thighs in the bottom of the crockpot.
In a medium bowl, mix together the pineapple chunks, bell pepper, onion, soy sauce, brown sugar, honey, garlic, ginger, and black pepper. Pour this mixture over the chicken.
Cover the crockpot and cook on low for 6-8 hours or on high for 3-4 hours, until the chicken is cooked through and tender.
If you prefer a thicker sauce, mix the cornstarch with water in a small bowl until smooth. Stir this mixture into the crockpot during the last 30 minutes of cooking.
Once cooked, shred the chicken with two forks and mix it back into the sauce.
Serve the chicken over cooked rice and garnish with chopped green onions.