Gather all ingredients before starting the recipe.
Combine 1/2 cup water, 1/4 cup distilled or white wine vinegar, 1/4 cup apple cider vinegar, 1 1/2 tbsp maple syrup or honey1 1/2 tsp kosher salt and 1 tsp Asian chili sauce (hot) in a microwave safe measuring cup and heat on high for 2 minutes.
Transfer 5 whole radishes and 1 medium red onion thinly siced to a jar with a tight fitting lid.
Pour vinegar mixture over the vegetables and make sure that they are fully covered.
Allow to cool for 30 minutes before using, or transfer to your refrigerator to use later.