Place the chicken in a bowl. Add the chopped oregano, olive oil and seasoning. Leave to marinate at room temperature for 2 hours.
Cook the chicken on a hot barbecue for about 6—8 minutes on each side, then remove, cut into chunks and keep warm.
Meanwhile, make the salad. Place the cucumber, tomato wedges, chopped red onion and parsley in a bowl. Add the olive oil and wine vinegar, toss well and season to taste.
Slice the haloumi into 8 and griddle the slices for 4 minutes on each side then serve with the chicken and salad.