In a bowl, combine all the ingredients and season with salt and pepper. Refrigerate until ready to serve.
Place a barbecue wok on one side of the grill. Preheat the grill, setting the burners to high. Oil the grate.
In a food processor, finely chop the broccoli and green onions until the size of couscous grains. Transfer to a bowl. Add the lamb and egg. Mix thoroughly and season with salt and pepper.
Working with lightly oiled hands, shape the meat into oblong sausages around flat metal skewers or disposable wooden chopsticks. Set aside on a plate. Brush lightly with oil.
In a bowl, toss the cherry tomatoes with the oil and cumin. Season with salt and pepper.
Adjust the grill to medium heat. Grill the kefta skewers for 10 minutes, turning several times, until cooked through and golden brown. Once the kefta have cooked for 5 minutes, place the tomatoes in the wok and cook for 5 minutes or until golden brown and beginning to burst.
Serve the kefta skewers and grilled tomatoes with the yogurt sauce, lemon wedges and couscous, if desired.