Cut the chicken into bite size pieces and put into a bowl. Add the cumin, coriander, sweet smoked paprika, cinnamon, chilli flakes, grated garlic and olive oil. Stir to combine and set aside for at least 30 minutes.
Make the yoghurt: coarsely grate the cucumber and toss with a pinch of sea salt. Allow to sit for 10 minutes then drain and squeeze out any excess water with a kitchen towel.
Peel and grate the garlic. Mix with the garlic and yoghurt and some freshly ground black pepper and put into a bowl and sprinkle with sumac.
Stir the grated cucumber into the yogurt and chill until needed.
Chop all the vegetables for the salad and toss in a bowl: the baby gem lettuce, cucumber, cherry tomatoes, celery, red onion.
Thread the chicken onto skewers.
Heat a heavy based pan or griddle over a medium high heat with a little drizzle of oil. Fry the skewers (you might have to do this in batches) until cooked and slightly charred.
Meanwhile whisk the red wine vinegar with salt, pepper and the extra virgin olive oil. Pour over the salad.
Warm the flat breads.
Serve the skewers scattered with chopped parsley and a good squeeze of lemon with the salad, yoghurt and flatbreads.
Notes
Basically a kebab worth firing up a winter BBQ for! The key to the most flavourful chicken truly is the time you marinade them in the spice mixture here.