SOAK corn in water 30 min.
HEAT barbecue to high heat. Remove husks and silk from corn. Grill corn, red pepper and onion slices 15 min., turning after 8 min. Cool 15 min.
CUT corn kernels from cobs; place in large bowl. Remove and discard skin and seeds from pepper. Chop pepper and onion slices. Add to corn along with remaining ingredients; mix lightly.