Shave the Brussels sprouts using a mandoline slicer or a sharp knife to create thin ribbons, about 1/16- or 1/8-inch thick. Discard any tough pieces and transfer the shaved sprouts to a large mixing bowl.
In a separate small bowl, whisk together the lemon zest, lemon juice, sea salt, and extra virgin olive oil until the mixture is well combined and emulsified. This will be your dressing.
Pour half of the dressing over the shaved Brussels sprouts and toss to coat evenly. Let the salad sit for about five minutes to allow the flavors to meld. After tasting, add more dressing if desired.
Finish the salad by adding the grated Parmesan cheese and black pepper. Adjust the seasoning with additional sea salt if needed. Toss everything together until well mixed and serve immediately for the best flavor and texture.