Place the diced cucumbers, onion, bell pepper, and garlic in a large mixing bowl. Combine with the salt and pour water over the mixture until covered. Let sit for at least 6 hours or overnight.
Drain the cucumber mixture in a colander, rinse thoroughly with water, and drain again.
In a large stock pot, add the sugar, vinegar, and spices and bring to a boil. Reduce the heat to medium-low and simmer for 5 minutes. Add the drained cucumber mixture and return to a boil. Reduce the heat to medium-low and simmer, uncovered, for 10 minutes. Discard the bay leaves.
Ladle the hot relish into hot sterile jars, leaving ¼ inch of headspace. Wipe the rims of the jars clean and seal tightly with the lids.
Process the jars in a boiling water bath for 10 minutes.
Sealed jars will store in a cool, dark place for a year. If the seal is broken, the relish will keep in the fridge for at least a month. Makes 4 pints (you can use pint-sized or half pint jars). Best eaten at least a week later after the flavors have had time to meld and the vinegar mellows out a bit.