Preparation

• To make the dressing, combine the white wine vinegar, Dijon mustard, onion powder, salt and pepper in a small bowl. Add the olive oil in a slow, steady stream, whisking as you go. Set the dressing aside.
  
  
  Cook the vegetables on the stovetop. For the potatoes, place the whole red potatoes in a small saucepan and cover them with cold water. Bring the water to a boil. Then, reduce the heat to a simmer and cover the pot. Cook until the potatoes are tender, about 15 to 20 minutes. Drain and discard the cooking water and let the potatoes cool before cutting them into quarters.
  
  For the green beans, blanching is best. Bring a small saucepan of salted water to a boil. When the water is boiling, add the green beans and cook for about 3 minutes, until they’re tender-crisp. Remove the beans to a bowl of ice water to cool them down.
  
  Divide the lettuce between two salad bowls. Top each plate with half of the potatoes, beans, tomatoes, olives, hard-boiled eggs and tuna. Drizzle the salads with dressing and serve any extra dressing on the side.
  
  
  
  Chef's notes:
  The 19th century century Niçoise salad recipe as it is kept in the archives in Nice, France consists of local ingredients:
  Tomatoes, Broad beans and/or small purple artichokes hearts, green Onions or radishes, local summer peppers, Basil, Anchovy, Nice black olives (small and specific to the region), Olive oil, Garlic, Salt pepper
  If we want to respect in an orthodox way the model of the Nicoise salad, we should not add anything more. Forget about the grilled tuna, it was a rich thing back then, nobody ate that. You'll also notice there's no egg: at that time, the Nicoise salad was really all raw - or at least, as far as anchovies and olives go, fermented, but not cooked.
  Dressing the salad: Traditionally, the Niçoise salad is laid out flat, so that all the ingredients are visible and well distributed. You should therefore take a large, slightly deep plate rather than a salad bowl.
  The local garlic, which is pink, will be used to rub the plate to flavor it. Do not put the minced garlic cloves directly in the salad, it would be too strong. Place the tomatoes in quarters first, then add all the other ingredients on top and drizzle with a little olive oil (and red wine vinegar if you like). A little salt if necessary and a turn of the pepper mill, a few chopped basil leaves, and it's ready.
  
  
  Nowadays, Niçoise salad has become a mix of various colorful ingredients consisting of potatoes, black olives, green beans, artichokes hearts, green onions, radishes, cucumbers, peppers, anchovies and vinaigrette dressing. Hard boiled eggs , tuna, (canned or fresh broiled and sliced) , grilled salmon pieces, or chicken are often the main proteins in the recipe.
  Some people say the salad is served on a bed of lettuce and others say that tomatoes are the base. And some do not arrange the elements of the salad at all, but just toss it all together.