Strip off the kale's ruffly leaves by grasping the bottom of each stem and pulling your hand up forcefully. Discard the stems. Stack the leaves, then use a large, very sharp knife to sliver them as thin as you can. Put the slivered kale in a large bowl.
In a small saucepan, heat the oil over medium heat and sauté the garlic, stirring frequently, until it's fragrant and just on the verge of browning, about two minutes. Add the salt and the sherry vinegar and stir as the vinegar sizzles furiously, until the whole thing becomes outrageously fragrant (about 45 seconds).
Pour the dressing over the kale and toss thoroughly with tongs. Stir in the Parmesan, add salt to taste, and serve the dish with extra cheese to be sprinkled on top.