In a medium bowl, whisk together the pineapple juice, soy sauce, brown sugar, ketchup, grated ginger, minced garlic, and sesame oil to create the marinade.
Reserve half of the marinade in a small saucepan for later. Pour the other half into a large zip-top bag or shallow dish. Add the chicken thighs, ensure they are fully coated, and marinate in the refrigerator for at least 30 minutes and up to 4 hours.
While the chicken marinates, cook the rice. Rinse the jasmine rice under cold water until it runs clear. In a medium pot, combine the rinsed rice, 2.25 cups of water (or broth), and a pinch of salt. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes. Turn off the heat and let it steam, covered, for another 10 minutes before fluffing with a fork.
Prepare the glaze. In a small bowl, whisk the cornstarch and 2 tablespoons of cold water to make a slurry. Bring the reserved marinade in the small saucepan to a simmer over medium heat. Whisk in the slurry and continue to simmer for 2-3 minutes, stirring constantly, until the sauce thickens enough to coat a spoon. Set aside.
Heat vegetable oil in a large skillet over medium-high heat. Remove chicken from the marinade, discarding the used marinade. Cook the chicken for 5-7 minutes per side, until golden brown and cooked through (165°F or 74°C).
In the last 2-3 minutes of cooking, add the drained pineapple chunks to the skillet to caramelize alongside the chicken.
Reduce the heat to low. Pour the thickened huli huli glaze over the chicken and pineapple. Toss gently to coat everything in the glossy sauce and let it bubble for one minute to meld the flavors.
Serve immediately by spooning the fluffy rice into bowls and topping with the glazed chicken and pineapple. Drizzle any extra sauce from the pan over the top and garnish with sliced green onions and sesame seeds.