Preheat grill. Prepare corn and brush liberally with olive oil. Place on grill and cook for 25-30 minutes or until kernels are tender, rotating every 10 minutes and allowing some kernels to char.
Remove corn from grill and allow to cool.Cut kernels away from cob. Discard cob and place kernels in a medium bowl with remaining ingredients. Mix well to combine. Refrigerate until ready to use, at least 4 hours or overnight.