In a small saucepan over medium heat combine together water, sugar, and salt. Stir until sugar and salt are dissolved. Bring this mixture to a gentle boil. And pour in the vinegar. Bring to a boil, again and set aside.
In your jars, combine daikon and thinly sliced red chili. Pour in the hot pickling solution mixture until the daikon is fully submerged in the pickling liquid.
Secure the lid and let the mixture cool at room temperature for 1 hour. After that, refrigerate for 12 hours (overnight) and enjoy.