1Break-trim the asaparagus. Obtain a flat-bottomed container, large enough to hold the asparagus flat. Pour in the cider vinegar, add the garlic and cayenne.
2Bring 1" water in a large flat frypan to a rolling boil. Using tongs, added small bunches of asparagus spears to the water, remove after 5 to 15 seconds (the asaparagus will become a vivid green) and immediately quench in, and leave in, the vinegar. Continue until all asparagus are in the vinegar. If necessary, add more vinegar so that the top layer is at least half submerged.
3Marinate for one to two hours, depending upon the stalks’ thickness, but no longer.
4Remove the asparagus from the vinegar, dry thoroughly wiping off any excess cayenne or garlic, and coat the spears with the olive oil. Coat a flat bottomed frypan with olive oil, preheat to medium-high heat, just short of smoking. Saute the asparagus in quantities such that they can be rolled to cook on all sides, doing that with pan shaking or the flat of a spatula, until they are partially blackened, about 2 minutes for thin stalks, up to 4 minutes for medium. Salt lightly (if at all) to taste, serve.
5Optional: An anchovy, oil, and bread crumb sauce goes well on these.