Chill the cheese. Place the string cheese in the freezer for 10–15 minutes while you set up — this prevents blowouts in the air fryer. If using wonton wrappers, cut each cheese stick in half first.
Wrap the sticks. Lay one wrapper flat on a clean surface with a point or edge facing you. Place the cheese stick near the bottom edge, leaving about an inch of wrapper below it. Brush water along all four edges of the wrapper.
Roll and seal. Fold the bottom edge up and over the cheese, fold both sides in toward the center (like wrapping a burrito), then continue rolling forward until sealed. Press the seam firmly so there are no gaps — gaps cause cheese leaks.
Arrange in the air fryer. Place the wrapped sticks in a single layer in a lightly greased air fryer basket, leaving space between each one. Work in batches if needed.
Spray generously. Spray both sides of the sticks with olive oil spray. Don't skip this step — it's what gives them that golden, crispy shell.
Air fry at 350°F for 5–8 minutes, flipping halfway through, until the wrappers are deep golden brown.
Rest and serve. Let the sticks rest for 2–3 minutes before serving (the cheese is molten). Serve with warm marinara, ranch, or your favorite dipping sauce.