1.Combine couscous with stock in large heatproof bowl; cover, stand about 5 minutes or until water is absorbed, fluffing with fork occasionally.
2.Melt butter in large frying pan; cook couscous, tossing with fork constantly until grains separate.
3.Meanwhile, combine tomato, capers, onion, parsley, vinegar and oil in medium bowl.
4.Serve chicken with couscous, tomato salad and hummus.
Purchase the barbecued chicken on the same day you serve it. Hummus is made from chickpeas, garlic, lemon juice and tahini (sesame seed paste) and can be purchased, ready-made, from most delicatessens and supermarkets.