Carefully peel back corn husks to within 1 in. of bottom; remove silk. Brush with 1 tablespoon oil. Rewrap corn in husks and secure with kitchen string. Place in a Dutch oven; cover with cold water. Soak for 20 minutes; drain.
Grill corn, covered, over medium heat for 25-30 minutes or until husks are blackened and corn is tender, turning often. Cool.
Cut corn from cobs; place in a large bowl. Stir in the remaining ingredients. Chill until serving.