Combine mango, pineapple, onion, cilantro, lime juice, salt, and jalapeño pepper in a medium bowl. Set aside.
Divide buffalo into 4 equal portions, shaping each into a 1/2-inch-thick patty. Sprinkle patties with jerk seasoning and 1/2 teaspoon salt. Place patties on grill rack coated with cooking spray; grill 5 minutes on each side or until done.