Place the chicken thighs in the slow cooker. Pour the honey, soy sauce, minced garlic, and black pepper over the top. Stir gently to coat the chicken evenly.
Cover and cook on low for 6 hours or on high for 3 to 4 hours until the chicken reaches an internal temperature of 165°F and becomes very tender.
About 20 minutes before serving, combine the rice and water in a medium saucepan. Bring to a boil, then reduce to a simmer, cover, and cook for 15 to 18 minutes until the water is absorbed and the rice is fluffy.
Fluff the rice with a fork. Serve the chicken thighs and sauce over the rice. Sprinkle the sliced green onions on top before eating.