1. Remove the husks from the corn and reserve.
2. Mix together the coarse chilli powder and sea salt and place on a small plate or saucer.
3. Cut the limes in half and set aside.
4. Cook the corn over a medium heat over a barbecue or under a medium hot grill for 4-5 minutes.
5. Turning them around so that they cook all over, until the corn is lightly charred in places.
6. Remove from the heat, dip a lime half in the chilli mixture and squeeze and spread it over the corn to coat evenly.
7. Repeat with the remaining corn, lime and chilli mixture.
8. Place the corn on the reserved husks and eat immediately.