How to Make It
In a blender, combine all of the ingredients except the lamb and puree until smooth. Transfer to a large bowl or resealable plastic bag, add the lamb and turn to coat. Marinate in the refrigerator for 18 to 24 hours.
In a large bowl, toss the cucumber and onion. In a medium saucepan, combine the sugar and salt with 3/4 cup of water and bring to a simmer, stirring to dissolve the sugar and salt. Remove the pan from the heat and stir in the vinegar; let cool slightly. Pour the warm brine over the cucumber and onion and let cool to room temperature, then refrigerate overnight.
Light a grill and oil the grate. Remove the lamb from the marinade and thread onto the skewers; season lightly with salt. Grill, turning, until lightly charred and medium within, 6 to 7 minutes total. Transfer the lamb to a platter and serve with the pickles.