Wash the cucumbers and slice them up in as even slices as possible. Clean the onion and slice it up as thinly as the cucumber. Do the same to the garlic.
1 kg Cucumber, 1 Yellow/brown onion
Take the clean jar and start layering the cucumber, onion and garlic. Add in dill and mustard seed in the jars as you go as well.
Once the jars are filled, pour over the pickling liquid. Make sure to cover the cucumbers before closing the lid.
Let stand in the fridge for a couple days to a week before trying it - letting it pickle so nicely on it's own. It might be hard to let them be, but it is well worth it!
Notes
You can put a glass weight on top of the cucumbers to make sure they are below the pickling liquid line if you want. - if you don't have a glass weight handy; a thick slice of lemon will do just fine. I don't really know how long these will last - They've always been finished before they've gone bad! But we've had them in the fridge for a couple weeks without any issues.