You don't need pickling cucumbers for this recipe - English cucumbers work very well, and as an added bonus, they don't need to be peeled or seeded. The thin slices stay crisp because of a preliminary salt brining, which means this recipe needs to be started a day in advance of cooking. Canning is a simple extra step which gives a 1-year shelf life to the pickles. These make welcome and delicious gifts, so consider doubling the recipe!
English (seedless) cucumbers, unpeeled (cut into 1/8-inch thick slices, 3 to 4 large cucumbers)
apple cider vinegar
brown or yellow mustard seeds
coarsely cracked black pepper
Combine the water and salt in a large pot and stir until the salt dissolves. Add the cucumber slices, cover the pot, and refrigerate overnight or up to 24 hours.
The next day, drain the cucumbers but don't rinse them. Set aside.
Place the vinegar and sugar in a large pot and cook over medium-high heat until the sugar dissolves.
Cut the onion in half through the stem end, then cut crosswise into very thin slices. Add the onion, cucumbers, mustard seeds, celery seeds, pepper, and turmeric to the pot and bring the mixture to a boil. Turn off the heat and ladle the hot cucumbers and their liquid into 4 hot 1-pint canning jars, leaving about 1/2 inch of headspace at the top of the jars. Seal the jars with clean lids and rings.
The pickles can be cooled and refrigerated for up to 2 weeks. Otherwise, to process the jars, use a canning bath or place a metal rack inside a large pot. Fill the pot with water and bring it to a boil over high heat. Add the sealed jars, setting them on the wire rack. The water must cover the jars by at least 1 inch. Cover the pan and boil for 10 minutes.
Remove the glass jars from the water bath and let them cool to room temperature. The lids need to set: if they look concave, the canning process has worked; your pickles will last up to a year if stored in a cool, dry place. If the lids have any play in them when pushed, refrigerate the jars and consume them within 2 weeks.