We start with the Yoghurt sauce by adding all the ingredients, except the lemon zest and the sumac, in a bowl, stirring well to combine. Place in a serving bowl, sprinkle on top the lemon zest and the sumac, cover and chill.
Make the spice blend by adding the Sichuan peppercorns, cumin and caraway seeds, chili flakes, sugar, salt & pepper in a spice mill or with mortar and pestle, coarsely grinding them.
Add the lamb cubes on the skewers without squeezing them towards each other. Sprinkle all over them the spice blend and use your hands to press the spice blend on the kebabs.
In the meantime, either prepare your coals or set your oven grill to medium-high.
For charcoal grilling place the skewers on direct heat, making sure that ash has been created over your coals so that you don’t burn the kebabs and cook for about 12’ turning every minute or so.
For the Oven grill place the skewers on a grated plate, making sure that you have oiled the grates with the canola oil. Cook for 12-14’ while turning over every 2’.
Serve, leaving the kebabs on the skewers, over pitta bread along with the yoghurt sauce and next to a salad, while topping with the lemon zest.