In a large bowl, whisk together the pineapple juice, soy sauce, brown sugar, vegetable oil, minced garlic, minced ginger, and black pepper until the brown sugar is fully dissolved.

Add the chicken breasts to the marinade and turn to coat all surfaces. Cover and refrigerate for at least 1 hour, or overnight for maximum flavor and tenderness.

Preheat your grill or stovetop grill pan over medium-high heat. Remove the chicken from the marinade, let the excess drip off, and discard the used marinade.

Grill the chicken for 6 to 7 minutes per side without moving it, until an instant-read thermometer reads 165 degrees F (75 degrees C) at the thickest part and the juices run clear.

Remove chicken from heat and let it rest on a cutting board for at least 5 minutes before slicing.

While the chicken grills, combine the jasmine rice, coconut milk, water, and salt in a medium saucepan. Stir once gently to coat the grains.

Bring to a boil over medium-high heat. Once boiling, reduce heat to low, cover with a tight-fitting lid, and simmer for 15 to 20 minutes until the rice is tender and all liquid is absorbed. Do not lift the lid during cooking.

Remove the rice from heat, fluff with a fork, and keep covered for 5 minutes to finish steaming.

Slice the rested chicken against the grain. Spoon coconut rice onto plates, top with sliced Hawaiian chicken, and garnish with sliced green onions and sesame seeds. Serve immediately.