Cut the daikon into 4-inch pieces, then slice each piece into small wedges. Place the cut daikon in a large mixing bowl, add salt, and toss to combine. Let the mixture sit for 2 hours to allow the water to pool at the bottom. Afterward, rinse the daikon and squeeze out the excess salt in batches.
Arrange the daikon on a wire rack set over a baking sheet and preheat the oven to its lowest setting, usually around 170°F. Allow it to dry for 1-2 hours, or longer if necessary.
In a small saucepan, combine the fish sauce, brown sugar, and water. Heat the mixture over medium heat until it begins to bubble, then remove from the heat. Allow it to cool to room temperature.
Transfer the dried daikon to a jar with a lid and add the sliced garlic and chili peppers.
Pour the brine into the jar and secure with a lid. Let it sit at room temperature for 24 hours, then transfer it to the fridge. It will be ready to eat after 1 day, but the flavor will improve with time. When stored in the fridge, it can last for up to 8 months.