Bring a large pot of water to a boil. Add trimmed haricot verts, then cook. Using tongs, transfer the string beans to an ice bath. Return the water to a boil. Drain the haricots verts. Leave whole or chop into bite-size pieces.
Season the boiling water with a generous 1-2 Tbsp of Kosher salt. Add the potatoes and cook until the potatoes are knife tender. Drain. Leave whole or halve.
Place lettuce leaves on a large platter, then add tuna, string beans, potatoes, hard boiled eggs, tomatoes, and olives, placing them in mounds around the tray. Scatter with anchovy fillets. Season.
Drizzle the entire salad with our Nicoise Salad Dressing, then dig in!