Candying the beets rather than simply baking them makes the chips beautifully translucent and sugary-crisp.
Preheat oven to 250 degrees. Slice beets very thinly into rounds, preferably on a mandoline. Bring water and sugar to a boil in a small saucepan, stirring constantly until sugar dissolves. Add beets. Reduce heat, and simmer until slightly translucent, about 30 minutes.
Using a slotted spoon, transfer beets in a single layer to a rimmed baking sheet lined with a nonstick baking mat. Bake until dry and slightly firm, about 1 hour.
Storage: Chips can be stored in an airtight container at room temperature for up to 2 days.