Peel the cucumbers.
Slice the peeled cucumbers in half lengthwise and use a spoon to scoop out the seeds.
At this point, you have half cucumber boats. Cut the boat in half, leaving a curved end at each end. Next, cut the half boats in half lengthwise, and then repeat. Each cucumber yields a total of 16 pieces, or 8 from each seeded half.
Mix the cucumber pieces with salt, and then add just enough water to cover. Allow them to sit for 8 to 12 hours, or overnight.
Drain the cucumbers.
Prepare your jars and add mustard seeds (and pickling spices if using) to each jar.
Add the vinegar and sugar to a pot and bring it to a boil. Add the cucumbers and boil for 1 minute.
Load the hot cucumbers into the jars and top with brine, leaving 1/2 inch headspace.
Process the jars in a water bath canner for 10 minutes for pints (or 15 minutes for quarts), adjusting for altitude.