1 medium sized red onion
1/2 cup white wine vinegar (or apple cider vinegar)
1 tsp. salt
optional seasonings: 1 tsp. chili powder or garlic powder for flavour

1. Thinly slice the onions, leaving them in rings for easy use
2. Place the rings into a pint size jar and sprinkle with the salt and other seasonings
3. Pour the vinegar over the rings to fill the jar and put the lid on
4. Leave at room temperature for two hours so flavours can meld
5. Transfer to the refrigerator for up to two weeks