Step 1

Add sliced onions to a medium bowl. Pour enough boiling water over them to fully cover and count to Drain onions and place in jar or bowl.

Step 2

Heat vinegar, lime juice, 1/8 cup sugar, chili flakes and salt in small saucepan over medium heat until sugar has dissolved, about 3 minutes.

Step 3

Taste for sweetness and add more sugar as needed.

Step 4

Pour vinegar mixture over onions.

Step 5

Allow to stand at room temperature, until fully cooled. Cover and refrigerate up to 2 weeks.