First make the marinade. In a large bowl mix the ginger, cumin seeds, Shaoxing wine, soy and sunflower oil. Add the lamb to the bowl, mix well and set aside to marinate for 30 minutes to one hour.
Meanwhile make the spiced rub. Place the cumin and Aleppo chilli in a small bowl, mix well and set aside.
Preheat a griddle pan until smoking or fire up the barbecue.
Divide the lamb and fat (if using) between the skewers, reserving the marinade in the bowl. Pinch the meat as you thread it through. This prevents it from rotating on the skewer when you flip it over.
Place the skewers on the grill and cook for 2 minutes on each side until you get nice char marks. Stir the sugar into the reserved marinade and brush over the skewers. Cook on both sides for another 30 seconds to 1 minute until glossy and slightly sticky. Set aside on a platter for 5 minutes.
To make the herb salsa, place all the salsa ingredients in a medium bowl with ⅛ teaspoon of salt and mix well. Sprinkle the spiced rub over the skewers and drizzle over the olive oil. Serve with the herb salsa scattered on top.