Our tasty version of a classic Nicoise salad can also be turned into a sandwich.
In a large pot of boiling salted water, cook green beans until bright green and tender, 3 minutes. Drain and rinse under cool water. In a small bowl, whisk together mustard, vinegar, shallot, and oil and season with salt and pepper. In a medium bowl, combine tuna with half the vinaigrette and stir gently to combine.
Divide lettuce among 4 bowls. Top with tuna mixture, green beans, eggs, tomatoes, and olives; season with salt and pepper and drizzle with remaining dressing. Serve immediately.
For a flavor upgrade, drizzle 6 halved plum tomatoes with olive oil and season with salt and pepper. Roast, cut side up, at 300 degrees until juices release and tomatoes shrivel slightly, 1 1/2 hours.