Add chicken to a slow cooker. Chop onion and mince garlic.
In a small bowl, whisk together the soy sauce, honey, vinegar, onion, garlic, pepper, and ginger. Pour mixture over chicken and cook on low for 4-5 hours until no longer pink in the middle (avoid over-cooking so it does not dry out).
Approximately 20 minutes before chicken is done cooking, make rice as directed on package. Once chicken is done, remove it from the crockpot and cut into smaller pieces.
Pour sauce from the slow cooker into a small sauce pan. Whisk water and cornstarch together in a small bowl and then add to sauce; heat over medium and whisk continuously until thickened.
Toss chicken back into slow cooker and add sauce; stir to coat evenly. Cover until ready to serve.
Cut broccoli into bite-sized pieces and then add to a microwave-safe dish along with 1/3 cup of water; cover and cook on high power for 4-5 minutes until tender.
Serve chicken over rice, sprinkled with sesame seeds; serve broccoli and pineapple on the side.