Wash the cucumbers thoroughly. Cut them into slices or spears according to your preference.
In a large mixing bowl, combine the sliced cucumbers and onions. Set aside.
In a small saucepan, bring the vinegar, water, sugar, pickling salt, mustard seeds, celery seeds, and turmeric to a simmer over medium heat. Stir until the sugar and salt dissolve completely. Remove from heat and let the brine cool for a few minutes.
Pour the cooled brine over the cucumber and onion mixture until they are fully submerged. If using garlic and dill, add them to the jars.
Pack the cucumber mixture into the glass jars, making sure to distribute the brine evenly among the jars.
Seal the jars with lids and refrigerate for at least 24 hours to allow the flavors to meld. For best results, let the pickles sit for 3-5 days before enjoying.
Serve the pickles cold as a delightful crunchy snack or side dish.