In small bowl, combine yoghurt, tomato a 1 tablespoon chives. Add salt and peper to taste and set aside. Cut artichoke pieces in half,set aside. In large saucepan, heat 1 tablespoon (15 ml) oil. Add onion and garlic; saute for 3 minutes. Add red pepper, saute for 2 minutes. Add chicken stock; cover and bring to a boil. Stir in couscous, currants, sun-dried tomatoes and artichokes. Cover and remove from heat. Let stand 5 minutes. Meanwhile, toast pinenuts in large frying pan for 2 to 3 minutes or until lightly browned. Remove and set aside. In same frying pan, heat remaining 1 tablespoon (15 ml) over medium high heat. Add chicken and saute for 3 minutes or until no longer pink inside. Stir chicken, pine nuts and salt and pepper to taste into couscous mixture. Remove to platter and garnish with remaining chives. Serve with yoghurt mixture.