01 - In a mixing bowl, whisk together the pineapple juice, soy sauce, brown sugar, olive oil, minced garlic, grated ginger, and black pepper until the sugar dissolves and the mixture is well blended.
02 - Place the chicken breasts in a zip-top bag or shallow dish. Pour the marinade over the chicken, ensuring each piece is thoroughly coated. Seal and refrigerate for at least 1 hour, or up to 4 hours for a more pronounced flavor.
03 - Preheat your grill or grill pan to medium-high heat, approximately 375°F to 400°F.
04 - Remove the chicken from the marinade, discarding the remaining liquid. Pat the chicken lightly to remove excess marinade. Grill the breasts for 6 to 7 minutes per side, or until the internal temperature reaches 165°F.
05 - During the last 2 minutes of grilling, place the pineapple rings directly on the grill grates. Cook until distinct grill marks form and the pineapple caramelizes slightly.
06 - Transfer the grilled chicken to a serving platter and top each breast with a grilled pineapple ring. Garnish with chopped fresh cilantro and lime wedges if desired. Serve immediately.