Bring a large pot of salted water to a boil. Add the potatoes and cook until tender, adjusting the heat so that the potatoes stay at a simmer, about 8 minutes. Drain and spread out on a rimmed baking sheet.
Meanwhile, in a large bowl, whisk together the olive oil, vinegar, scallions, shallots, mustard, parsley, basil, thyme, dill and salt and pepper.
Pour the vinaigrette over the warm potatoes on a baking sheet and gently toss and spread them out again. Allow the potatoes to cool to room temperature, and soak up the dressing. Adjust seasonings to taste. Transfer to a serving bowl and serve at room temperature.
You will want to use waxy, non starchy potatoes for potato salad, which tend to hold their shape better. They also have thin skins, which means you don’t have to peel them unless you want to. And for this salad I went with baby potatoes, and cut them into thin slices before cooking them, about ¼-inch thick. You could definitely go with larger waxy potatoes, red or white or yellow. You can cut those into ½ inch cubes, or cut them into quarters, and then slice the quartered potatoes ¼-inch thick.