The proper, traditional Salade Niçoise is a salade composée. Mine is not so composée. In fact, I often pare it back to the barest of essentials, transforming it into a hot potato salad.
an egg for each person
tuna, if so desired
Start by bringing a pot of water to the boil with a little salt.
Do not peel your potatoes; skin is awesome. Scrub them, however, and chop them into bite-sized chunks. I like redskin or yukon gold potatoes. Tiny new potatoes or fingerlings are also clearly delicious.
When the water is boiling, add the potatoes. Turn the heat back to low, cover, and let simmer until the potatoes are done. The time will depend on the size of chunks; start checking them in twenty minutes or a half hour.
In the meantime, top and tail green beans and chop into inch-long pieces.
Also, make the dressing.
white wine vinegar
chopped herbs of choice
salt, pepper, maybe some mustard
Put a 6:1 ratio of olive oil and white wine vinegar in a measuring cup or container of some type suitable for whisking. Wash and chop some (a lot) of whatever fresh herbs you have on hand; I had dill and parsley. Add some salt and pepper, and mustard if you like mustardy dressings. Whisk with a fork until it's correct and unctuous.
I made mine in the salad bowl, which I would not recommend. You want to pour it over the hot vegetables later; make it in a pouring device.
Are the potatoes getting soft? Do you think they'll be done in ten minutes or less? Good; add the egg, put the lid back on, and cook for another ten minutes or so. At maybe seven or eight minutes, add the green beans. When the beans are done, in 2-3 minutes, you are all ready.
Remove your egg to some cold water. Drain your vegetables. Put them in a bowl and pour the dressing over them. You want the vegetables as hot as possible at this point, so they absorb the dressing well. Mix to get dressing on everything.
Whack your cooled egg all over with a spoon, peel it, and chop it into appropriate chunks. Add it to the salad. Splash some extra dressing on top, if you want.
Extra herbs can go over the top of each serving, with a couple grinds of salt and pepper. Add some tuna from a can, flaked, if you want. If you have real tuna on hand, you could even sear it and serve little filets over the salad. I am not that fancy, or at least I wasn't tonight. Anyway, I like fully cooked fish.
In this case, however, I had no fish and was yet well satisfied.