Heat broiler. Place the potatoes in a large saucepan of water and bring to a boil. Reduce heat, cover, and simmer until fork-tender, about 15 minutes. Drain and remove from pot.
Meanwhile, coat the salmon with 2 teaspoons of the oil and season with ½ teaspoon salt and ¼ teaspoon pepper.
Broil the salmon 10 to 12 minutes, until just cooked through. Let cool, then flake with a fork.
Meanwhile, place the green beans in a saucepan of water and boil until crisp-tender, about 3 minutes. Drain, run under cold water, and set aside.
In a medium bowl, whisk together the herbs, mustard, lemon juice, remaining ⅓ cup oil, and ¼ teaspoon salt. Set aside.
Cut the potatoes in half when cool enough to handle. Arrange with the lettuce and green beans on plates. Top each with the salmon, eggs, and olives. Drizzle with the dressing.