Step 1

Put a kettle of water on the stove to boil. Place the sliced onions in a heat-proof and non-reactive bowl (glass or ceramic). When the water boils, pour it over the onions to cover. Stir and let sit for about 10 seconds, then pour into a colander to drain.

Step 2

Return the onions to the bowl and add the lime juice and salt. Stir to mix well. Let sit for 30 minutes before serving. Store in a covered glass container in the refrigerator for up to 3 weeks.