Peel the ginger root.
Using a mandoline or a sharp vegetable peeler, slice the ginger as thinly as possible.
Place the ginger slices in a colander, cover them generously with the salt, and let them sit for 10 minutes. This step helps to draw out excess moisture.
Rinse the ginger slices thoroughly under cold water to remove all the salt, then gently pat them dry.
In a clean glass or ceramic jar, whisk together the Sushi Rice Dressing and mirin.
Add the rinsed ginger slices to the jar. If you're making pink ginger, add the slice of beetroot now.
Seal the jar and shake well to ensure all the ginger is coated in the pickling liquid.
Let the ginger marinate for at least 10 minutes before using. For the best flavor, let it sit for a few hours or overnight.
Discard the beetroot slice before serving.
Store any leftovers in the sealed jar in the refrigerator for up to one month.