How to Make It
Using a sharp knife, peel the tangerines, removing all of the bitter white pith. Working over a small bowl, cut in between the membranes to release the sections. Squeeze the juice from the membranes into the bowl and discard the membranes. Transfer the tangerine sections to a large bowl, reserving 1/4 cup of the tangerine juice.
In a small bowl, whisk the 1/4 cup of tangerine juice with the sherry vinegar, Dijon mustard and olive oil and season with salt and pepper.
Add the arugula, onion and pistachios to the bowl with the tangerine sections and toss. Using a vegetable peeler, shave the ricotta salata over the top. Season the salad with salt and pepper and toss with 1/3 cup of the dressing. Serve, passing the remaining dressing at the table.