Add the sliced onions into a glass jar with a lid.
Squeeze the limes and pour over the onions, just enough to cover the sliced onions in the jar.
Screw on the lid, and shake to ensure all onions are submerged in the lime juice. Pop in the fridge for at least 4 hours, overnight is perfect. Can be stored for up to 2 weeks.
Recipe Note
Try replacing the limes with lemon or combining the juice of both!
