Preheat the air fryer to 200 degrees Celsius.
Slice the halloumi block into 1 centimeter thick rectangular pieces or uniform cubes.
In a mixing bowl, toss the halloumi slices with olive oil, dried oregano, and chili flakes until evenly coated.
Place the halloumi pieces in the air fryer basket in a single layer, ensuring no overlap to allow for maximum airflow.
Cook for 5 minutes, then use silicone-tipped tongs to flip each piece.
Cook for an additional 3 to 5 minutes until the surface is golden brown and the edges are crispy.
Remove from the air fryer and serve immediately while hot with a squeeze of fresh lemon juice.