Add all ingredients to a food processor and blend until emulsified. Adjust seasoning to taste, then set aside. Alternatively, you can add the ingredients to a bowl and whisk until smooth.

Rinse and dry all vegetables before you start cooking.

Place baby potatoes in a pot of cold, salted water and bring to a boil. Cook 15-20 minutes or until fork tender. Drain, then set aside to cool.

Place eggs in a single layer in a large pot. Fill with enough water to cover. Bring to a rolling boil, then remove pot from heat. Let eggs stand in the hot water for 10-12 minutes, then drain and rinse with cold water to stop the cooking process. Peel eggs, cut each one in half, and set aside.

Placed green beans in a pot of water, and cook until just barely tender (about 3 minutes). Plunge the cooked beans into a bowl of ice water to maintain the bright green colour. Drain and set aside.

Use a potato masher, or a fork, to press down on the cooled potatoes until they crack. You don't want to completely smash them, just break them enough so they can absorb the dressing.

Arranged the lettuce in a single layer on a large platter. This is the base of your salad. Arrange the cracked potatoes on top of the lettuce, along with the eggs, prepared vegetables and olives. Spoon the tuna out of the cans to avoid adding excess oil to the salad. You can either add the tuna directly to the platter, or place in a small bowl next to it.

Season the salad with a pinch of salt and freshly ground black pepper, if desired. Serve immediately with the dressing.

Refrigerate unused portions promptly.