My Favorite Summer Seafood Salad - from Nice

Every summer, when the farmer's market starts having most of the fresh ingredients for my favorite Salad Nicoise, I make a big one, and we have it for dinner and then lunch the next day. It's great for entertaining, because you can make the whole thing before your guests arrive and keep it in the fridge until you're ready to serve it.
     This is a layered salad, not a tossed salad - all of the ingredients should be visible. With a nice bottle of wine and some crusty bread, you can close your eyes and picture yourself on the French Riviera. Only the French could make potato salad this scrumptious.

Here's how I do it:

TUNA SALALD NICOISE
This is an easy French-inspired summertime meal that has something for everyone, and uses loads of fresh market ingredients.
Total Time: About 30 mins      Makes: 4 - 6 servings
INGREDIENTS
For the dressing:
1/4 cup good quality balsamic vinegar
1/2 teaspoon Dijon mustard
1 large chopped shallot
French Sea Salt
Freshly ground black pepper
1/2 cup extra-virgin olive oil
2 tablespoons finely chopped fresh herbs, such as parsley, tarragon, or chives
For the salad:
8 - 10 ounces new potatoes, white, red & purple
French Sea Salt
6 ounces fillet green beans
Freshly ground black pepper
4 large eggs, hard boiled and peeled
8 ounces fresh ahi or albacore tuna, seared & baked or grilled & chilled
8 ounces yellow cherry  tomatoes or sliced large tomatoes
10 ounces Bibb or butter lettuce (about 1 head), washed, dried, and torn into
bite-sized pieces
8 anchovy fillets, rinsed and patted dry
1/2 cup black olives, such as niçoise or kalamata 
INSTRUCTIONS
For the dressing: Whisk the vinegar, mustard, and a large pinch each of salt and pepper in a medium, glass or non-metallic bowl until combined.  Whisk in the olive oil in a slow, steady stream. Stir in the herbs, taste, and season with more salt and pepper as needed; set aside.
For the salad:
Sear and bake the fresh ahi or albacore tuna so that it is still a little pink on the inside. A 1” thick piece of  tuna will require 1 minute of searing each side, then another 3-4 minutes in a 425° oven. Or grill for 2 minutes per side. Set aside. (Fish will continue cooking, so err to the rare). 
Place the potatoes in a medium saucepan. Add enough water to cover by 2 inches; bring to a boil over high heat. Reduce the heat to medium and gently boil until the potatoes are easily pierced with a knife, about 10 minutes. Using a slotted spoon, transfer the potatoes to a cutting board until cool enough to handle but still warm. (Do not let the potatoes cool completely.) Meanwhile, return the water to a boil over high heat. Add a little salt, then add the green beans and 
blanch until tender but still crisp, about 2 to 3 minutes. Drain and rinse under cold running water until cool. Spread the beans on paper towels and let them sit until dry. When the potatoes are ready, slice them in half.  Place in a small bowl and toss with just enough of the dressing to lightly coat.
     Taste, adding more dressing, salt, and pepper as needed; set aside.Slice each egg lengthwise into quarters and set aside. Place the green beans,  tuna, and tomatoes in separate small bowls. Toss with just enough of the dressing to lightly coat. Taste, adding more dressing, salt, and pepper  as needed; set aside. Arrange the lettuce in a large wooden or ceramic salad bowl. Place the potatoes in the center of the lettuce, then the tomatoes, crumbled tuna and green beans over the potatoes. Top with the anchovy fillets, egg quarters and olives. Serve immediately and, if you choose, with remaining dressing on the side.
     Add a chilled bottle of Pouilly Fume and some crusty bread and you have a meal fit for a Roi!