I found a recipe on allrecipes.com and modified it a little bit to fit the ingredients that I had on hand.
Trim the ends of the asparagus spears and cut them into pieces that will fit into a pint jar (about three inches). Place them in a large bowl with 1/3 cup of coarse sea salt and cover them with two quarts of water. Let stand for two or more hours. Drain and rinse under cool water, pat dry.
Sterilize four pint size wide mouth jars in simmering water for five minutes.
In a saucepan over medium heat, combine 3 1/3 cups of distilled white vinegar, 1 1/3 cups of sugar, 2 teaspoons of course salt, 2 teaspoons of mustard seeds and 1 teaspoon of dill weed (or 3 tsp. dill seed).
Add one onion, sliced or chopped. I used red onion because that's what I had on hand and I like red onions the best, but it does turn the pickling liquid pink, which turns the asparagus a little pink, too.
Bring to a boil and boil for one minute.
Pack the asparagus spears, tips up, in the hot jars leaving. If you have some dill sprigs, tuck one into each jar, then sprinkle in 1/4 teaspoon of red pepper flakes. Pour hot pickling liquid into the jars, filling to within 1/4 inch of the rim. Wipe rims with a clean damp cloth, and seal with lids. Process in a boiling water bath for 10 minutes.
Cool to room temperature. Check seals when cool by pressing the center of the lid. It should not move. If any jars have not sealed properly, refrigerate and eat within two weeks.
This recipe made four pints.
It's pretty good if you like pickled things. I can only take it in very small doses because of it's sweet-tartness. It also has a little bite to it because of the red pepper, which I do like. I think I might like the onions that it's pickled with better than the asparagus.