In a medium bowl, whisk together the granulated sugar, ground cinnamon, and salt until well combined, then set aside.

Lightly flour a clean work surface. Unfold the thawed puff pastry sheet onto the surface and gently roll or stretch it into an even rectangle.

Brush the entire surface of the puff pastry with the melted butter, making sure to reach all the edges.

Sprinkle the cinnamon sugar mixture evenly over the buttered pastry, then gently press the sugar into the dough with your hands so it adheres.

Using a sharp knife or pizza cutter, cut the pastry lengthwise into 12 strips, each about 1 inch wide.

Pick up each strip by the ends and twist in opposite directions several times to form a tight spiral, then place the twisted strips on a plate or tray.

Preheat the air fryer to 350°F.

Arrange the twisted strips in a single layer in the air fryer basket, leaving space between each twist so the air can circulate. Work in batches if needed.

Air fry at 350°F for 8 to 10 minutes, flipping halfway through, until the twists are puffed, deep golden, and crisp.

Transfer the cooked cinnamon twists to a wire rack and let them cool slightly so the bottoms stay crisp.

For an optional glaze, whisk together the powdered sugar and milk or water in a small bowl until smooth.

Drizzle the glaze over the slightly cooled cinnamon twists and serve warm or at room temperature.