Preheat oven to 300° F.
In a large mixing bowl, combine sugar, salt, and cinnamon.
In a separate mixing bowl, whisk together egg whites, water, and vanilla extract.
Pour walnuts into egg mixture and toss to coat.
Pour coated walnuts into sugar mixture and mix well.
Spread walnuts on a rimmed baking sheet lined with parchment paper.
Bake at 300° for 20 minutes. Stir; then bake for another 15-20 minutes.
Remove from oven; set pan aside to cool.
Once cooled, break walnuts apart and store in an airtight container at room temperature.