Cut the asparagus, including the tips into very thin slices, crosswise and place in a medium bowl. Add the red onion and pecorino and toss to combine. Dress with the vinegar, olive oil and salt and toss again. This salad should be fairly heavily dressed. The vinegar will sort of "cook" or tenderize the asparagus.
It is best to do this about an hour or so in advance to let the flavors "marry".