Dressing: Shake ingredients in a jar.

Cook ptoatoes: Boil potatoes until tender. Drain and leave to fully cool. Slice into halves.

Blanch beans: Boil green beans until tender or done to your liking. Drain and refresh under cold running water to quickly cool. Drain, pat well to dry.

Arrange the cos leaves on a large, wide plate.

Scatter and layer the remaining ingredients artfully around the plate, finishing with the eggs, olives and chunks of tuna. Drizzle with dressing over and serve!