1/4cuprice wineOR: apple cider or plain white vinegar
The amount of liquid depends on how many cucumbers, etc. you use, so you have to adjust accordingly.
Thinly slice cucumbers & onion. Soak for a few minutes in equal amounts of vinegar and water (1/4 cup each or so), and also a pinch of sugar and a pinch of kosher or sea salt. Add chopped herbs if using.
Done in about 20 minutes, but can be kept in pickling liquid for several days and up to a few weeks even.