Add the olive oil in a thin stream, whisking constantly.
1 cup Extra Virgin olive oil
Add about 1/3 of the vinaigrette, the scallions, and the parsley to the potatoes, tossing to coat them completely, and chill in the refrigerator for at least half an hour.
2 tbsp scallions, 4 tbsp fresh parsley
Combine another 1/3 of the vinaigrette with the tuna, tossing gently so as to leave rather large chunks of meat.
8 oz tuna
Line a large salad bowl with the lettuce leaves and place the potatoes on the bottom of the bowl.
1 large romaine lettuce
Arrange the tomato wedges, egg quarters, tuna chunks, olives, anchovies, and green beans in an attractive pattern.
4 large tomatoes, 3 large hard-cooked eggs, 1/2 cup black olives, 2 cups string beans, 12 large anchovy fillets
The dish may be prepared several hours in advance up to this point and refrigerated.
Spoon the remaining vinaigrette over the salad just before serving and sprinkle the parsley on top.
3 tbsp parsley
Serve with warm French bread.
Notes
Soak the anchovies in cold water for 10 minutes then drain and dry on paper towel.