Add water and cornstarch in a saucepan. Stir in soy sauce, brown sugar, garlic and ginger. Heat over medium high heat, whisking constantly until bubbly and thick, about 5 minutes.
Add pork to the marinade and mix well. Allow to cool before covering and refrigerating for 30 minutes, or overnight.
When ready to cook, preheat air fryer for 5 minutes at 400 degrees.
Thread pork onto bamboo skewers and place into air fryer basket, working in batches if necessary. Reserve remaining marinade. Heat at 400 degrees for 6 minutes. Flip over and use a pastry brush to spread reserved marinade onto skewers. Cook for an additional 2 minutes. Season with salt and pepper before serving.