Marinate the Chicken: In a large bowl, combine soy sauce, olive oil, minced garlic, grated ginger, salt, and black pepper. Add the chicken and toss to coat. Let marinate for at least 15 minutes.
Prepare the Oven and Baking Sheet: Preheat the oven to 400°F (200°C). Line a large baking sheet with parchment paper or lightly grease it.
Arrange Ingredients on the Sheet Pan: Spread the marinated chicken pieces evenly on the baking sheet. Scatter the chopped bell pepper, red onion, and pineapple chunks around the chicken for even roasting.
Bake the Dish: Place the sheet pan in the oven and bake for 20-25 minutes, stirring halfway through, until the chicken is fully cooked and the vegetables are tender.
Garnish and Serve: Remove from the oven and garnish with fresh cilantro, green onions, and sesame seeds if desired. Serve hot over rice or alongside your favorite side dishes.