Add sliced vegetables to a mason jar or glass container. Set aside.
To a small saucepan add vinegar of choice, water (if using), salt, and sugar. Bring to a simmer over medium heat and stir to fully dissolve salt and sugar. Taste and adjust flavor as needed, adding more salt or sugar to taste.
Pour the brine over the vegetables, ensuring they are fully submerged. If needed, add more vinegar or a little water to cover. *When pickling cucumbers, we generally like to let the brine cool so the cucumbers maintain their color and crunch.
Seal well and shake to combine. Then refrigerate for at least 1 hour. The flavors will deepen and intensify the longer it marinates. Best flavor is achieved after 24 hours.
Will keep in the refrigerator for 2-3 weeks (sometimes longer). Not freezer friendly.
*Nutrition information calculated with onion for the sliced vegetable and with the lesser amount of salt.