I am creating a fathers day feast including: duck breast in wine reduction with candied kumquats potato, celery root, and chanterelle gratin and some sort of vegetable side which I cannot decide upon... I would like something sort of light and fresh as the gratin provides enough richness to the plate. My only idea is a cauliflower and green olive salad (with capers, parsley, and sherry vinegar), but I'm not sure if this will clash with the rest of the meal. Do you think this would harmonize with the other dishes sufficiently? Any better suggestions?