To Prep
Place the radish slices, onions and chillies loosely into a mason jar (or divide into a few smaller jars).
To Cook
In a saucepan, mix the Pickle ingredients, stirring until the sugar is dissolved. Heat on high and bring to boil, then remove from heat.
To Pickle
Immediately pour the mixture into the jar(s) and use a heavy spoon to sit on the vegetables to ensure they are fully submerged. Let cool to room temperature and cover to sit overnight.
Place the jars in the fridge and serve after 2-3 days, up to 6 mths.