Rinse mussels thoroughly and scrub under running water. Discard any mussels that are not tightly closed.
Cook mussels in boiling water and remove from pan as soon as they open, to prevent overcooking them. Discard mussels that do not open. Cool.
Open mussels with a knife and place half on a serving dish.
Combine in a medium size bowl, onion, red hot pepper, tomato, parsley, corn, ají, oil, key lime juice, salt and pepper. Let mixture stand for 15 minutes.
Place approximately 1 ½ tablespoon of this mixture over each mussel.
Serve with lime wedges.
3 – 4 servings