Start by bringing the water to a boil in a pot. Once boiling, add the rice along with a pinch of salt. Cover the pot, reduce the heat to a simmer, and let it cook for 15 minutes until the rice is tender. Fluff the rice and set it aside.
Next, heat the olive oil in a pan and add the sliced chicken breasts. Cook for 5–7 minutes, stirring occasionally, until the chicken is browned. Season the chicken with soy sauce, hoisin sauce, rice vinegar, sesame oil, garlic powder, ginger (if using), salt, and pepper. Stir everything together until the chicken is well-coated in the sauces.
After the chicken is cooked, add the sliced red bell pepper, broccoli florets, and corn kernels to the pan. Continue to cook for another 2-3 minutes, or until the vegetables are tender but still maintain a crisp texture.
Finally, serve the cooked rice in bowls and top it with the stir-fried chicken and vegetables. Garnish each bowl with chopped green onions and a sprinkle of sesame seeds.