Shave the onion very thinly, following the curvature of the onion and preserving the integrity of the onion's cell wall structure. It matters.
Throw in the salt. Toss. Toss again. One more time. Good.
Now, add the lime juice. Tumble the onion a couple of times.
Let the onion mixture sit for 10 minutes at room temperature.
Right before serving, add the cilantro. Not a second sooner.
Serve atop Cocoa-Crusted New York Strip, grilled meats, hearty roasts, or...pretty much anything in the universe. Thank Maria. She'll feel good inside.