Pop the skewers in a dish or bowl of water and set aside to soak (this will help stop them catching and burning). Tip the chicken into a large bowl. Peel and grate in the garlic. Zest the lemon and place the zest in a separate bowl.
Cut the lemon in half and squeeze the juice from one half into the bowl with the chicken. Sprinkle in 1 tsp dried oregano. Drizzle in 1 tbsp each red wine vinegar and olive oil. Season with salt and pepper and mix together. Set aside to marinate for 10 mins.
Peel and thinly slice the onion. Halve the tomatoes. Dice half the cucumber. Add both to a small bowl. Squeeze over the remaining lemon half. Add a pinch of salt and toss together. Roughly chop the mint leaves. Add to the salad. Set aside.
Heat your grill to medium-high. Cut the courgette into 1cm-thick rounds. Thread the chicken onto the skewers, adding a courgette slice every now and then. Place the skewers on a foil-lined baking tray. Arrange any leftover courgette around them.
Slide the kebabs under the grill and cook for 10-12 mins till cooked through and slightly blackened. Turn once or twice to cook evenly.
Tip the yogurt into the lemon zest bowl. Add a little salt and pepper and mix together.
Wrap the tortillas in foil. When the chicken has nearly finished cooking, place the tortillas under the kebab grill pan and leave them there to warm for 3-4 mins.
Carefully unwrap the tortillas (mind the steam and hot foil). Spread a little of the lemon yogurt onto each one. Add a handful of the tomato salad. Using a fork, slide the grilled chicken and courgette pieces from the skewers and pile on top of the salad. Wrap up and eat.