Cook pearl couscous following packet directions. Drain and cool.
Combine red wine vinegar and reserved tuna oil to make a dressing and set aside.
Combine ingredients, except haloumi in a large serving bowl. Drizzle with dressing.
Heat a large hot non stick frypan, spray with oil and cook haloumi for 1 minute on each side or until golden. Add to salad. Serve immediately.
Chopped fresh parsley can be used as an alternative to mint in this salad.