In a large bowl, toss the prawns with the olive oil, lemon juice, salt, and pepper. Let marinate for about a half hour while you heat up the grill. Grill prawns on each side until they turn pink, about 5 minutes depending on size.
Remove the peel and pith from the limes and cut between the membranes to remove the segments. Put these "supremes" into a bowl and squeeze over the juice from the membranes. Add the remaining ingredients and mix; season with salt and pepper. Place warm grilled prawns on a platter and top with salsa.
Recipe courtesy of Tyler Florence