Wash and dice potatoes, cook until soft yet still firm. Cut and blanch green beans in a size consistent with potatoes. Cool both items well. Dice onion and celery; toss with olives, beans and potatoes. In a separate bowl mix oil, mustard, water, lemon juice, and zest with parsley. Mix well. Toss gently with potato mixture. Adjust seasoning with salt and pepper. Chill. Preheat grill or sauté pan very hot. Lightly coat tuna steaks with salt, pepper and oil. Sear quickly until medium rare, approximately 3 minutes on each side (longer based on your preferences). Spoon salad on center of plate, add tuna to top and serve immediately. You may also cut tuna and fold it into salad for a side dish.
Nancy and Tim Bass - Sunburst Tomato