Preheat the oven to 300°F. Line a large baking sheet with parchment paper.
In a small bowl, stir together the sugar, cinnamon, and salt.
In a large mixing bowl, whisk together the egg white, water, and vanilla until very light and foamy, about 1 minute. Add the pecans and stir to coat.
Sprinkle in the sugar mixture, then stir until the pecans are evenly coated. Spread out the coated pecans evenly in a single layer on the prepared sheet pan.
Bake for 20 minutes, then stir the nuts. Continue baking until the pecans smell toasted and fragrant, and the coating is dry, about 15 minutes more. Let the nuts cool completely on the pan. (The sugar will harden as they cool). Break up any chunks of pecans and serve immediately or store them in an airtight container for up to 2 weeks.
