In a blender, combine the oil, onion, garlic, parsley, cumin, lemon zest, lemon juice and salt and puree until smooth. Transfer the marinade to a resealable plastic bag and add the lamb. Seal and refrigerate for at least 6 hours or preferably overnight.
Light a grill or preheat a grill pan. Drain the lamb, shaking off the excess marinade. Thread the lamb onto 4 long skewers. Grill over high heat, turning occasionally, until lightly charred, about 5 minutes for medium-rare meat.
Sesame Sauce:
Add yogurt, tahini and lemon juice to a large bowl and stir to combine. Season with salt and pepper, to taste.
In a small skillet, toast the sesame seeds and cumin seeds until fragrant.
Spread the sesame sauce on a large serving plate and drizzle with the olive oil. Sprinkle with toasted seeds and parsley. Arrange the grilled lamb skewers on top. Serve.
Notes
Grill the lamb just the way you like using a meat thermometer and this temperature guide:
Rare: 115ºF – 124ºF (very pink inside)
Medium rare: 125ºF – 135ºFF (bright pink inside)
Medium: 136ºF – 144ºF (light pink inside)
Medium well: 145ºF – 154ºF (barely any pink left)
Well done: 155ºF (no pink)
Note: The USDA recommends cooking lamb to an internal temperature of 145 degrees with a 3 minute rest. Pro tip: The residual heat will continue to cook the meat after it’s off the grill. To avoid accidentally overcooking the lamb, check the temperature with a meat thermometer and take the kabobs off the grill once the internal temperature is 5 degrees less than your desired doneness.