1 red onion halved and thinly sliced
1/2 cup apple cider vinegar
1/4 cup freshly squeezed lime juice
1/8 cup sugar
1/2 tablespoon kosher salt
1. Add sliced onions to a medium bowl. Pour enough boiling water over them to fully cover and count to 10. Drain onions and place in jar or bowl.
2. Heat vinegar, lime juice, 1/8 cup sugar and salt in small saucepan over medium heat until sugar has dissolved, about three minutes.
3. Pour vinegar mixture over onions.
4. Allow to stand at room temperature, until fully cooled. Cover and refrigerate up to 2 weeks.