1.In a medium bowl, combine lamb with harissa and cumin. Cook lamb on heated oiled grill plate (or grill or barbecue). Remove from pan; cover and stand 5 minutes, then slice thinly.
2.Meanwhile, finely grate 2 tsp rind from oranges. Segment oranges over a small bowl, reserving 2 tbsp juice.
3.Combine couscous, rind and boiling water in large heatproof bowl. Cover and stand about 5 minutes or until water is absorbed, fluffing with fork occasionally. Stir in orange segments, reserved juice and mint; season to taste. Serve with lamb.