Place coconut in a small frying pan over medium heat. Cook, stirring frequently, until coconut is golden and lightly toasted. Transfer to a bowl.
In a small bowl, combine lime juice and sugar.
Preheat BBQ grill or a grill pan to medium heat. Oil grill. Put pineapple slices on grill and apply lime juice mixture using a brush. Cook for 2-3 minutes, turn and baste again with lime juice mixture. Cook until softened and browned in spots, approximately 7 to 8 minutes in total.
Transfer pineapple to a dish and sprinkle with remaining lime mixture, lime zest and toasted coconut.