01 - Whisk together soy sauce, pineapple juice, olive oil, garlic powder, and black pepper in a bowl. Add chicken breasts and coat thoroughly. Marinate for at least 15 minutes, up to 2 hours for deeper flavor penetration.
02 - Combine soy sauce, pineapple juice, brown sugar, and rice vinegar in a small saucepan. Bring to a simmer over medium heat. Stir in cornstarch slurry and cook for 1-2 minutes until sauce thickens to desired consistency. Remove from heat and set aside.
03 - Heat grill or grill pan to medium-high temperature, approximately 375-400°F.
04 - Remove chicken from marinade and grill for 5-6 minutes per side until internal temperature reaches 165°F. During the final 2 minutes of cooking, place pineapple rings on the grill and cook until lightly caramelized with grill marks.
05 - Lightly toast burger buns on the grill for 30-60 seconds until golden and warm.
06 - Spread mayonnaise on bottom bun if desired. Layer with lettuce leaf, grilled chicken breast, drizzle of teriyaki sauce, grilled pineapple ring, tomato slice, and red onion. Complete with top bun.
07 - Serve immediately while chicken and pineapple are still warm. Pair with sweet potato fries or crisp salad if desired.