Preheat the oven to 300℉, and grease a rimmed baking sheet or line it with parchment paper.
In a large bowl, whisk the egg white with water until frothy. (I do this with a fork or small whisk.) Add the pecans and gently toss to coat.
In a small bowl, combine the sugar, cinnamon, and salt. Pour over pecans and mix thoroughly.
Transfer the nuts to the prepared baking sheet, spreading in an even layer, and bake for 45 minutes (see notes below), stirring and spreading back out, every 15 minutes. When done, spread on another baking sheet and cool thoroughly.
Storage: Stored in an air-tight container, the pecans will stay fresh on the counter for several days. I like to store them in the refrigerator where they will stay fresh for several months...not that they will last that long! The spiced pecans freeze well too.
Notes
Using a dark-coated pan or your oven cooks on the hot side? In this case, I recommend reducing the oven temperature to 275℉ to avoid over-browning.