Rinse the rice under cold water until the water runs clear.
In a medium saucepan, combine the rice, water, and salt. Bring to a boil over high heat.
Once boiling, reduce heat to low, cover, and simmer for 18-20 minutes, or until all the water is absorbed and the rice is tender.
Remove from heat and let stand, covered, for 5-10 minutes. Fluff with a fork before serving.
In a medium bowl, whisk together the soy sauce, pineapple juice, brown sugar, rice vinegar, garlic, and ginger.
Add the chicken cubes to the marinade and toss to coat evenly.
Let the chicken marinate for at least 15 minutes, or up to 30 minutes in the refrigerator.
In a small bowl, whisk together the cornstarch and water until smooth (cornstarch slurry).
In a separate bowl, combine the soy sauce, pineapple juice, brown sugar, ketchup, and rice vinegar. Set aside.
Heat the vegetable oil in a large skillet or wok over medium-high heat.
Remove the chicken from the marinade (discard the marinade) and sprinkle with the 2 tablespoons of cornstarch, tossing to coat evenly.
Add the chicken to the hot skillet and cook, stirring occasionally, until browned and cooked through, about 5-7 minutes.
Remove the chicken from the skillet and set aside.
Add the chopped bell pepper and onion to the skillet and cook, stirring occasionally, until softened, about 3-5 minutes.
Pour in the soy sauce mixture and bring to a simmer.
Add the pineapple chunks and cornstarch slurry to the skillet. Stir constantly until the sauce thickens, about 1-2 minutes.
Return the cooked chicken to the skillet with the pineapple sauce. Toss to coat evenly.
Serve the Pineapple Chicken And Rice over a bed of fluffy rice.
Garnish with sliced green onions, sesame seeds, and red pepper flakes (if desired).