Using a spoon, peel the ginger, then slice it roughly with a sharp knife. Slice the onion into quarters.
You will need lemon juice and lemon zest. Using a zester, zest the lemon and juice it. Add everything to the bowl of the food processor.
Add soy sauce, rice wine vinegar, and brown sugar to the bowl of the food processor.
Blitz the ingredients until you get a runny chunky paste. You don't want it to be a very smooth paste, so take it easy and use the pulse option.
