Preheat the oven to 300°F (149°C). Line 2 large baking sheets with parchment paper or silicone baking mats and lightly grease with nonstick spray. Set aside.

In a large bowl with a handheld or stand mixer fitted with the whisk attachment, beat egg whites and water on medium-high speed until foamy and fluffy, about 2 minutes. Add the sugar, cinnamon, and salt, and fold with a silicone spatula until combined.

Add the pecans and stir to coat completely. Spread the nuts in a single layer on the prepared baking sheets and bake for 45 minutes, stirring every 15 minutes. Halfway through baking, rotate the baking sheets and swap their positions in the oven.

Allow to cool completely on the baking sheets. The sugar coating will continue to crisp up as it cools.

Store pecans in an airtight container at room temperature for up to 3 weeks or freeze for up to 3 months. Thaw at room temperature.