Preheat an outdoor grill for medium heat and lightly oil the grate. Coat pineapple slices with cooking spray.

Cook pineapple on the preheated grill until lightly browned and caramelized, 5 to 10 minutes. Transfer pineapple to a cutting board to cool, then chop.

Combine pineapple, bell pepper, onion, cilantro, jalapeño, lime juice, garlic, sugar, salt, and black pepper together in a bowl. Refrigerate until chilled and flavors blend, about 1 hour.