Arrange all the salad ingredients nicely on a platter—greens on the bottom, topped with egg slices, olives, tomatoes, anchovies, and tuna, if using. Or—less attractive but easier to serve—toss all the ingredients together.
Make the vinaigrette by adding the vinegar to the oil, along with the salt and pepper, garlic, shallot, and mustard. Stir and taste. Add more vinegar if necessary and adjust the seasoning. Stir or shake vigorously, pour over the salad, and serve.
