Cut the potatoes. Slice each potato lengthwise into halves, then cut each half across so you end up with “fat” quarters.
Start them in cold water. Transfer the potatoes to a large 6-quart pot, leaving enough room for them to move. Pour in enough cold water to cover them by about two inches.
Boil until tender. Set the pot over high heat and bring the water to a boil. Add the kosher salt, lower the heat to medium-high, and boil for 8-10 minutes. They’re ready when the tip of a knife can pierce the potatoes easily.
Whisk the vinaigrette. While the potatoes cook, combine the extra virgin olive oil, red wine vinegar, lemon juice, lemon zest, garlic, parsley and chives in a small bowl or 1-cup measuring cup. Whisk until the vinaigrette is emulsified.
Drain thoroughly. Drain the potatoes, then shake them to release as much water as possible. Return them to the hot pot so the heat can help with any residual water.
Dress and season. Pour the vinaigrette over the warm potatoes and toss until coated. Taste, then add additional salt or pepper as needed.
Let the flavours develop. Leave the salad to marinate at room temperature for at least 1 hour and up to 4, then serve at room temperature.