French
Boil the potatoes in salted water until tender, 15-20 minutes, adding the green beans for the last 4 minutes. Drain, then put the beans in cold water to cool.
Boil the eggs for 9 minutes, cool them in cold water, then peel and quarter them.
Whisk the vinegar, mustard, shallot, salt and pepper, then whisk in the olive oil to make a vinaigrette.
Halve the warm potatoes and toss them with 2 tbsp of the vinaigrette.
Cut the tomatoes into wedges and tear the lettuce into large pieces.
Arrange the lettuce on a platter and top with the potatoes, green beans, tomatoes, eggs, chunks of tuna and the olives.
Drizzle with the remaining vinaigrette and serve.