Mix the lime wedges with the salt and sugar. Pack into a sterilised jar and leave to ferment for four weeks.
When four weeks have elapsed, heat the oil in a pan, add the spices and fry until the seeds start to pop. Add the limes with all their juice, along with the cider vinegar, and cook for five minutes.
Leave to cool, then pack back into the jar and store for another week, so the flavours can combine.