Preheat oven to 300 degrees F. Line a rimmed baking sheet with parchment paper or a silicone baking mat.
In a medium bowl, whisk together the sugars, cinnamon, salt and cayenne, making sure there are no lumps.
In a large bowl, whisk the egg white and water until very frothy. Add the nuts, and stir to coat evenly. Sprinkle the nuts with the sugar mixture, and toss until evenly coated.
Spread the nuts in a single layer on the prepared baking sheet. Bake for 30 minutes, stirring twice during baking. Remove from the oven, and stir and separate the nuts as they cool. Once completely cool, the nuts can be stored in an airtight container or glass jars at room temperature or in the refrigerator for up to 1 month.