1. Heat 1/4 cup of the oil in a large skillet over medium-high heat. Add the drained potatoes, 1 teaspoon of the salt, and 1/2 teaspoon of the pepper, and cook, shaking the pan occasionally, until golden brown on both sides, 8 minutes.

2. Add the remaining tablespoon of oil, garlic, and drained green beans. Stir to combine and cook for 1 minute.

3. Add the tomatoes and olives and cook until the tomatoes are warmed through, stirring occasionally, 2 minutes. Remove from the heat.

4. Add the mayonnaise, lemon juice, minced onion, hard-boiled egg, capers, parsley, and tarragon and stir to combine. Taste and adjust seasoning, if necessary.

5. Combine the lettuce with the Creamy Parmesan Dressing and toss to coat. Arrange 3 or 4 leaves along the side of 6 large plates. Spoon the vegetables along the other side of the plate. Let sit while cooking the tuna.

6. Season each tuna portion with 1/2 teaspoon of the remaining salt, and 1/4 teaspoon of the remaining pepper.

7. Heat the remaining 1/4 cup of oil in 1 large skillet or 2 medium skillets, over medium-high heat. Add the tuna and sear, about 15 seconds per side. Remove from the pan and cut each crosswise into 4 equal pieces. Arrange the tuna slices down the middle of each plate, and serve.

8. For Creamy Parmesan Dressing: Bring a small saucepan of water to a boil. Add the egg and cook for 30 seconds until coddled.

9. In a small bowl, combine the salt, pepper, garlic, and anchovies. Mash the anchovies with the back of a fork and mix into the other ingredients. Add the egg and whisk well to combine.

10. Add the cheese, lemon juice, and mustard, and whisk well. Add the olive oil in a steady stream, whisking constantly. Add the Worcestershire and pepper sauces, and whisk well. Taste and adjust seasoning, if necessary.