A simple salad bar using the traditional Nicoise for inspiration is an easy way to make meals, particularly during the summer. Feel free to scale the recipe up or down depending on how many are at your table.
Make the dressing by pounding the garlic and anchovies in a mortar and pestle or mincing on a cutting board. Transfer to a small bowl and add the Dijon, lemon juice, and vinegar. Whisk well. Drizzle in the olive oil while whisking until blended. Whisk in the tarragon as well as freshly ground black pepper to taste.
Put the potatoes into a medium pot, cover generously with water, and add a few teaspoons of salt. Bring to a boil until tender enough to easily cut in half. Use a slotted spoon to scoop potatoes from the pot, set aside, and cut in half when cool enough to touch.
Hard boil the eggs by putting them in a small pot covered by 1 inch with water. Bring to a boil, remove from heat, and leave for 12 minutes. Put the eggs under running water until cool enough to peel and slice in half.
Arrange the potatoes, green beans, eggs, lettuce, tomatoes, tuna, and olives on a large platter. Lightly season the eggs, potatoes, and green beans with salt and pepper. Set the platter in the middle of the table with dressing on the side, and let everyone assemble their own salad. You may have leftover dressing, which will be good for another few days, stashed in the fridge.