Preheat your oven to 300°F (150°C) and prepare a large baking sheet by lining it with a Silpat baking mat or parchment paper. Set aside.

In a medium-sized mixing bowl, combine the granulated sugar, light brown sugar, ground cinnamon, and salt. Whisk together until the mixture is evenly blended and free of clumps.

In a large mixing bowl, whisk the egg white, vanilla extract, and water together until the mixture becomes frothy. Add the pecan halves to the bowl and gently stir to ensure each pecan is thoroughly coated with the egg white mixture.

Gradually sprinkle the sugar and cinnamon mixture over the pecans, tossing continuously to ensure an even coating. The sugar mixture should cling to the pecans, creating a uniform layer.

Spread the coated pecans out in a single layer on the prepared baking sheet. Bake in the preheated oven for 30 to 45 minutes, stirring the pecans every 15 minutes to prevent sticking and ensure even baking. During this time, the sugar coating will harden, forming a crisp shell around the pecans.

Once baked, remove the pecans from the oven and allow them to cool completely on the baking sheet. Once fully cooled, transfer the candied pecans to an airtight container. Store them at room temperature for up to one month, ensuring they remain fresh and crunchy.