Place the skewers in cold water to soak (this helps stop them burning during cooking). Peel and crush the garlic. Finely grate the zest from the lemon. Mix the garlic with half the lemon zest and squeeze in the juice from one lemon half. Add 1 tsp cumin, a pinch of salt and pepper, then the lamb. Stir to coat. Leave to marinate till ready to use.
Reserve 2 tsp of flour for rolling out. Sift the remaining flour into a large bowl. Add 1 tsp baking powder. Make a well in the middle, add 1 tbsp olive oil, then gradually mix in 2-3 tbsp water to form a smooth dough. Add the water 1 tbsp at a time till you have the consistency you want.
Tip the dough out and knead for 2 mins till smooth and elastic. Return to the bowl, cover loosely with a tea towel and leave to rest.
Peel and thinly slice the onion and put it in a bowl. Squeeze in the remaining lemon juice. Add the remaining zest. Stir and set aside. Chop the mint leaves (discard the stalks) and stir them into the yogurt. Set aside.
Thread the lamb onto the skewers and grill for 8-10 mins, turning once or twice, till browned and cooked through.
While the lamb kebabs cook, divide the dough into 2 pieces. Dust your work surface with the flour you reserved in step 2 and roll them out into flat rounds. Heat a dry frying pan or griddle for 2-3 mins till smoking hot. Cook the breads 1 or 2 at a time, for 2 mins on each side till charred and puffed up.
Serve the lamb kebabs on top of the breads, with the salad and a dollop of minty yogurt.