Combine cucumber or red onion with all other ingredients in a small container (the tighter everything is together, the better). Shake well and set in fridge for several hours, up to several days. The longer it sits, the better it's going to taste! FACT.
All the veg may not be submerged in liquid at first and that's ok. Even over this small amount of time, the molecules will break down and eventually it will all get covered! Science!