In a medium bowl, whisk together the pineapple juice, soy sauce, brown sugar, rice vinegar, sesame oil, minced garlic, and grated ginger. Place the chicken pieces in the bowl, ensuring they are fully submerged. Cover and marinate in the refrigerator for at least 30 minutes (up to 4 hours for best flavor).

While the chicken marinates, rinse the Jasmine rice in a fine mesh strainer under cold water until the water runs clear. In a medium saucepan, combine the rinsed rice, coconut milk, water, sugar, and salt. Bring to a boil over medium-high heat, then reduce to low, cover, and simmer for 15-20 minutes until liquid is absorbed. Turn off heat and let sit covered for 10 minutes. Fluff with a fork.

Heat 1 tablespoon olive or coconut oil in a large skillet over medium-high heat. Remove chicken from marinade (reserve marinade), pat dry slightly, and cook in a single layer for 3-4 minutes per side until golden and cooked through. Remove and set aside. Repeat if needed.

In the same skillet, add chopped red and green bell peppers. Sauté for 4-5 minutes until tender-crisp. Add pineapple chunks if using and cook for 1-2 minutes until caramelized.

Pour reserved marinade into the skillet. Mix cornstarch and 1 tablespoon water into a slurry and whisk into the skillet. Simmer for 2-3 minutes until thickened. Return chicken to skillet and toss to coat.

Serve the Hawaiian Chicken over coconut rice, garnished with green onions and sesame seeds.