In a medium bowl, combine the diced pineapple, mango, soy sauce, honey, olive oil, minced garlic, ground ginger, black pepper, salt, and lime juice. Mix well to create a marinade.
Place the chicken breasts in a resealable plastic bag or shallow dish and pour the marinade over the chicken. Seal the bag or cover the dish and refrigerate for at least 1 hour, or up to 4 hours for more flavor.
Preheat your grill to medium-high heat. Remove the chicken from the marinade, allowing excess marinade to drip off.
Grill the chicken for 6-7 minutes on each side, or until the internal temperature reaches 165°F. During the last few minutes of grilling, you can add any leftover marinade to the grill for added flavor, ensuring it cooks thoroughly.
Once cooked, remove the chicken from the grill and let it rest for 5 minutes before slicing.
Serve the grilled chicken topped with the fresh mango and pineapple mixture and garnish with cilantro if desired.