No mayo here! Boiled new potatoes are smashed and tossed with red-wine vinegar, lemon, and olive oil while still warm, then finished with parsley and oregano for a fresh, herby take on the classic.
In a large pot, cover potatoes with 2 inches water and season generously with salt. Bring to a boil, then reduce heat to medium-high and continue boiling until potatoes are fork-tender, about 9 minutes. Drain, transfer to a bowl, and lightly smash. Toss with vinegar, lemon juice and zest, and oil; season with salt and pepper. Let cool completely, about 30 minutes.
Stir in onion, parsley, celery leaves, and oregano. Season with salt and pepper. Serve, or refrigerate in an airtight container up to 1 day (bring to room temperature before serving, about 30 minutes).