For six as a first course:
Mince the garlic. In an small bowl, whisk together the vinegar, lemon juice, garlic, salt, and pepper. Continue whisking while adding the olive oil in a thin stream to produce a creamy vinaigrette.
Coat the tuna with two tablespoons of the vinaigrette. Sear on both sides over hot charcoal and slice thin.
Trim the green beans, boil until just tender, and refresh under cold running water. Boil the potatoes until barely soft and slice. Hard-boil the eggs. Mince the scallions. Slice or halve the Roma or cherry tomatoes, respectively.
Toss the lettuce (using only the soft leaves) with two tablespoons of the vinaigrette amd spread on a large platter. Toss the tuna, green beans, potatoes, tomatoes, scallions, basil, and oregano with the remaining vinaigrette and arrange over the lettuce. Cover with the olives, capers, and anchovies. Quarter the eggs (longitudinally) and arrange along the perimeter of the salad.