3 tablespoons white wine vinegar  | 
                                                2 tablespoons water  | 
                                                1 1/2 teaspoons dijon mustard  | 
                                                1/2 teaspoon olive oil  | 
                                                1/8 teaspoon freshly ground pepper  | 
                                                1/4 pound fresh green beans  | 
                                                2 small round red potatoes (about 1/4 pound)  | 
                                                2 tablespoons julienne-sliced sweet red pepper  | 
                                                1 tablespoon chopped purple onion  | 
                                                1 (6-ounce) tuna steak (3/4 inch thick)  | 
                                                1/2 teaspoon olive oil  | 
                                                vegetable cooking spray  | 
                                                2 cups torn fresh spinach  | 
                                                4 cherry tomatoes, quartered  | 
                                                1 tablespoon sliced ripe olives  |