Bring water to a boil in a saucepan. Remove from the heat, and stir in couscous. Cover and let stand for 10 minutes, then fluff with a fork. Set aside to cool slightly.
Mix olives, red bell pepper, sun-dried tomatoes, and couscous together in a bowl. Stir about 1 tablespoon liquid from olives and 1 tablespoon oil from sun-dried tomatoes into the couscous mixture until moistened. Add more oil as needed. Fold in feta cheese; sprinkle with parsley.