Place ham cubes in a food processor. Cover and process until finely chopped. In a medium bowl combine chopped ham, celery, and onion. For dressing, in a small bowl combine mayonnaise, pickle relish, and basil. Pour over ham mixture; stir gently to coat. Cover and chill for 1 to 4 hours. Serve ham salad on croissants or over wedges of cantaloupe. Makes 4 to 6 main-dish servings.