Pre heat he BBQ to high. Meanwhile, put the red onion, the juice of a lime and a pinch of salt into a bowl. Toss together and leave to macerate whilst you make the salad.
Toss the pineapple in a tablespoon of the oil and bbq for about 1-2 minutes a side, until just charred but still really firm. Cut into 1 inch chunks and chuck them into a salad bowl.
Whisk the remaining lime juice together with the remaining olive oil, the sugar and a pinch of salt.
Chuck the red onion, cucumber, coriander, chilli and dressing into the bowl with the pineapple. Mix together and serve immediately.
