Combine vinegars, olive oil, a generous pinch of salt and some freshly ground black pepper in a mason jar. Shake to combine.
In a large bowl, combine the brussels sprouts, persimmons, and hazelnuts. Slowly drizzle the vinaigrette on the salad and start turning it with your hands to coat.
Shave a generous amount of Parmigiano Reggiano onto the brussels sprouts and continue mixing. Add more vinaigrette and Parmigiano Reggiano as necessary. Taste and season with sea salt and freshly ground black pepper.