Hard-boil the eggs, peel them, and set aside.

Boil the new potatoes in water with 1 tablespoon of salt until tender, then drain and let cool before cutting into cubes.

Trim the ends of the green beans and blanch them in boiling water until crisp-tender, then cool in ice water.

In a large bowl, combine the potatoes, green beans, black olives, flat parsley, and chives.

In a separate bowl, whisk together the olive oil, lemon juice, white wine vinegar, garlic, Dijon mustard, capers, chopped black olives, salt, and black pepper to make the vinaigrette.

Drizzle the vinaigrette over the salad and gently toss to combine.

Cut the hard-boiled eggs into quarters and arrange on top of the salad before serving.