To Make Quick Pickled Onions: Thinly slice 1 medium onion. In a medium bowl, combine 2 tablespoons vinegar (I like apple cider vinegar), 1 tablespoon of salt, 1 tablespoon of sugar, and 4 tablespoons of hot water, and stir to dissolve the salt and sugar. Add the onion to the vinegar mixture and add enough cold water so that everything is covered. Give it a stir and put it in the fridge for about 20 minutes; rinse, drain, and serve. Optionally, you can also add crushed mint, which I did here.