Pat the chicken dry and cut into 1-inch pieces. Mince the garlic and dice the red pepper.

In a bowl, whisk soy sauce, pineapple juice, honey, rice vinegar, and 1 tbsp water. Set the sauce aside.

Heat oil in a large skillet over medium-high until shimmering. Add chicken in a single layer and cook for 4 to 5 minutes, turning once, until browned and no longer pink inside. Remove chicken to a plate.

In the same skillet, add the diced red pepper and garlic. Sauté for 1 to 2 minutes until fragrant and slightly softened.

Return the chicken to the skillet. Pour in the sauce and bring it to a gentle boil. Reduce heat to medium-low and stir in pineapple chunks.

Stir the cornstarch slurry, then add it to the skillet. Cook for 1 to 2 minutes, stirring, until the sauce thickens and becomes glossy.

Fold in the cooked rice and chopped green onions. Toss gently until the rice is evenly coated and heated through, about 1 to 2 minutes.

Plate the dish, sprinkle with sesame seeds and crushed red pepper if using, and serve hot.