You need 15 skewers: if wooden, soak in water for 10 mins. Cut chicken into 3cm pieces and place in a bowl. Add 1 tbsp olive oil, the spices, garlic and vinegar, toss well and season. You can do this up to a day before and refrigerate.
Thread 2-3 pieces on each skewer. Pour remaining oil in a frying pan or rub onto a griddle pan. Get the pan hot and sear the chicken for 3-4 mins on each side - you may have to do this in batches, keeping the cooked skewers warm in a low oven. Serve with smoky aÃ¯oli if you like.