Heat 1 tablespoon vegetable oil in a large skillet over medium-high heat.
Add the chicken pieces, season with salt and black pepper, and cook for 5-6 minutes until browned and fully cooked.
Remove from the pan and set aside.
In a small bowl, whisk together soy sauce, honey, rice vinegar, pineapple juice, garlic, ginger, and red pepper flakes.
In a separate bowl, mix cornstarch and water to create a slurry.
In the same pan, add the bell peppers and cook for 2 minutes until slightly softened.
Add the pineapple chunks and cook for another 1 minute.
Return the chicken to the pan.
Pour in the sauce and stir well.
Add the cornstarch slurry and stir until the sauce thickens (about 2 minutes).
Serve hot over cooked rice.
Garnish with green onions or sesame seeds if desired.