Soak 16 skewers in warm water for 20 minutes then drain.
Cut the chicken and haloumi into even-sized cubes (about 2cm-3cm) and thread on to skewers (each skewer should have 4-5 pieces of chicken and 2 pieces of haloumi).
Combine the olive oil, mint, garlic and lemon zest in a bowl. Spoon this mix over the skewers, rubbing it in to coat well. Put the celery leaves, tomatoes, cucumber, onion, coriander and parsley in a bowl then pour over the extra virgin olive oil and lemon juice. Season with salt and freshly ground black pepper and toss the salad to combine.
Heat a barbecue or grill plate to hot. Season the skewers then grill for about 5 minutes, turning, until golden and cooked through. Serve with the salad and flat breads.