To make the vinaigrette. Add all of the ingredients to a small bowl and whisk together. Set aside.

Boil the eggs. Bring a small pot of water to a boil. Then, turn off the heat (so there's no bubbles) and gently add the eggs. Turn the heat back up to boil and cook the eggs for 6½ to 7 minutes for a slightly jammy yolk. If you prefer hard-boiled eggs, cook for another 3 to 4 minutes.

Chill the eggs. Use a slotted spoon or skimmer to remove the eggs to an ice water bath for a few minutes. Then crack, peel, and halve each one.

Cook the potatoes. While the eggs are boiling, bring a separate medium pot of salted water to a boil. Add the potatoes, reduce the heat to a simmer, and cook until tender, about 15 minutes. Use a slotted spoon to remove the potatoes (leaving the hot water in the pot), transfer them to a cutting board, and let them cool. Then slice in half.

Blanch the beans. Add the green beans to the pot and simmer for 1 to 2 minutes, until they turn bright green. Then chill in an ice water bath and drain the beans in a colander.

Assemble the Nicoise salad. Spread the salad greens out onto a large platter. Arrange the potatoes, green beans, tuna, tomatoes, olives, red onion, and soft-boiled eggs on top. Season with kosher salt and freshly ground black pepper. Drizzle the lemon vinaigrette over the salad. I use about half the vinaigrette and save the remainder in the fridge for future use.