1. Preheat oven to 400°F. Arrange pineapple cubes, red bell pepper cubes, and red onion wedges on ungreased rimmed baking sheet. Drizzle with toasted sesame oil and vegetable oil, sprinkle with brown sugar, and season with salt and pepper, if desired. Toss to coat.
2. Roast pineapple mixture on center oven rack 30 minutes, or until lightly browned, turning once. Remove from oven and sprinkle with sweetened coconut flakes, if using, then drizzle with lime juice. Remove to serving bowl and toss well to combine. Serve hot or at room temperature.