Cook the Rice:
Rinse the white rice under cold water until the water runs clear. In a rice cooker or pot, combine the rice, water, and a pinch of salt. Cook according to the rice cooker instructions or bring to a boil, then reduce heat to low, cover, and simmer for about 18-20 minutes until the rice is tender and the water is absorbed. Fluff with a fork and set aside.
Prepare the Chicken:
In a skillet or wok, heat the vegetable oil over medium-high heat. Add the chicken pieces and cook until they are browned and cooked through, about 6-8 minutes. Remove the chicken from the skillet and set aside.
Make the Teriyaki Sauce:
In the same skillet, add the soy sauce, water, honey, brown sugar, rice vinegar, sriracha or hot sauce, minced garlic, and grated ginger. Stir to combine and bring to a simmer over medium heat.
In a small bowl, mix the cornstarch with water to create a slurry. Add the slurry to the sauce, stirring continuously until the sauce thickens, about 2-3 minutes.
Combine the Chicken and Sauce:
Return the cooked chicken to the skillet with the teriyaki sauce. Stir to coat the chicken evenly with the sauce and cook for an additional 2-3 minutes until the chicken is heated through and well-coated with the sauce.
Serve:
Divide the cooked white rice among serving bowls. Top with the spicy teriyaki chicken, spooning extra sauce over the chicken and rice.
Garnish with sesame seeds and sliced green onions if desired.