01 - In a medium bowl, whisk together the soy sauce, pineapple juice, brown sugar, olive oil, minced garlic, grated ginger, and black pepper until the sugar dissolves and the mixture is well combined.
02 - Place the chicken breasts in a large resealable plastic bag or shallow dish. Pour the marinade over the chicken, turning each piece to ensure even coating. Seal and refrigerate for at least 30 minutes, or up to 4 hours for deeper flavor penetration.
03 - Preheat an outdoor grill or grill pan to medium-high heat (approximately 400°F). Lightly oil the grates to prevent sticking.
04 - Remove the chicken from the marinade, allowing excess to drip off. Discard the remaining marinade. Grill the chicken for 5–7 minutes per side, or until the internal temperature reaches 165°F and juices run clear.
05 - While the chicken cooks, place the pineapple rings on the grill. Cook for 2–3 minutes per side until lightly charred and caramelized grill marks appear.
06 - Transfer the grilled chicken to a serving platter and top each breast with grilled pineapple rings. Garnish with thinly sliced green onions and sesame seeds if desired. Serve immediately.