Step 1

If using large cucumbers, cut in half lengthwise and scoop out seeds with a spoon. Discard the seeds.

Step 2

Combine the diced cucumbers, onions and peppers in a large stock pot. Sprinkle the ¼cup kosher salt over the vegetable. Fill the pot with ice cold water enough to cover the diced vegetables. Set the mixture aside to rest for 2 hours.

Step 3

Line a fine mesh sieve with cheesecloth and add the vegetables. Allow them to drain for 10 minutes, then gather the ends of the cheesecloth together and twist to form a bundle. Squeeze a little tighter to press out the liquid, allowing it to drain. Don't smash the vegetables but gently extract as much liquid as possible.

Step 4

While the vegetables are draining, combine the vinegar, sugar, celery and mustard seeds in the large pot.

Step 5

Bring the mixture to a boil and add the vegetables.

Step 6

Stir and bring it back to a boil. Reduce the heat and simmer for 10 minutes.

Step 7

Using a slotted spoon, place the hot relish in glass jars with lids. Spoon additional brine over the vegetable if needed to cover. If preserving, process according to standard canning procedures.

Step 8

If not canning, cool the jars then store the jars of relish in the refrigerator. This relish will keep for several weeks if refrigerated.