Build a fire in a charcoal grill, light a gas grill, or preheat a grill pan. 

Slice a pineapple into thick round slices. 

Oil the grates, and then set each slice of pineapple down carefully. Let them grill for 3-5 minutes, or until they develop nice dark grill marks, then turn slices carefully and repeat. 

Meanwhile, dice a red bell pepper, a half to a whole green jalapeño pepper, and half a red onion. 

Chop the pineapple into a medium-large dice (don't dice it too small, or it won't hold its texture), and mix with the vegetables. 

Dress to taste with lime juice, salt, and chopped cilantro. Garnish with cilantro.