Cut the pomegranate in half then pop all the seeds from the cases by either flexing the casing or hitting the curved side of the fruit with a wooden spoon and catching the fruit in a bowl. Transfer to a liquidiser or pestle and mortar and grind until a rough puree.
Pour the pomegranate puree into a plastic bag, add the honey, vinegar, allspice, pepper, salt, garlic and orange rind and mix together then add the cubed lamb. Seal the bag well, squeeze the bag to mix the meat and marinade together then put on a plate and chill in the fridge for three hours or overnight.
When ready to cook, thread the lamb on to 8-12 metal skewers, depending on size and cook over a medium barbecue or under a preheated grill for 15 minutes, turning once or twice and brushing with the marinade.
Meanwhile, add the couscous to a mixing bowl, add the oil, lemon rind and juice, little salt and pepper and boiling water. Cover bowl with a plate and leave to soak for five minutes. Scatter the pomegranate seeds and mint over the top then fluff up with a fork. Arrange cooked kebabs on top, sprinkle the onion around the kebabs and serve immediately.