01 - Combine soy sauce, pineapple juice, olive oil, garlic powder, and black pepper in a bowl. Add chicken breasts and marinate for at least 15 minutes, up to 2 hours for enhanced flavor.
02 - In a small saucepan, mix soy sauce, pineapple juice, brown sugar, and rice vinegar. Bring to a simmer over medium heat. Stir in the cornstarch slurry and cook for 1-2 minutes until thickened. Set aside.
03 - Preheat grill or grill pan to medium-high heat.
04 - Grill marinated chicken breasts for 5-6 minutes per side until fully cooked (internal temperature 165°F). During the last 2 minutes, grill pineapple rings until lightly caramelized.
05 - Lightly toast burger buns on the grill.
06 - Spread mayonnaise on the bottom bun if desired. Layer with lettuce, grilled chicken breast, drizzle with teriyaki sauce, top with grilled pineapple ring, tomato, red onion, and finish with the top bun.
07 - Serve immediately while warm.