Salad nicoise for summer guests

This is a lovely dish to make in the summertime. I use good-quality Italian-style tinned tuna (in olive oil of course!). I drain the oil from the canned tuna to use in the vinaigrette, adding extra virgin olive oil to make 5 tablespoons, then adding 2 tablespoons lemon juice, garlic, a spoonful of mustard, and salt and pepper (thanks to Jamie Oliver for teaching me the universal ratio of 5:2 oil to liquid... works for all salad dressings, whether the liquid is lemon juice or vinegar or whatever). The baby rocket (arugula) was first tossed in a little of this vinaigrette and then laid down as a base. On top: boiled potatoes, the tuna, tomatoes, and boiled eggs. Usually I would also add briefly cooked green beans. Serve with gorgeous bread. Delish.