Place the prepared potatoes into a large saucepan, submerge them in water, and season generously with salt. Bring the water to a rolling boil, then reduce the heat and allow the potatoes to simmer for approximately 10 minutes, or until they are just tender. Drain thoroughly and let them steam-dry for five minutes.
Preheat the air fryer to 200°C. Transfer the potatoes back into the still-warm pan, then shake them gently to roughen the edges. Drizzle with oil, season to taste, and toss well to ensure an even coating.
Arrange the potatoes in a single layer inside the air fryer basket. Cook for 30 to 35 minutes, shaking the basket at the halfway mark to promote even browning. If necessary, use tongs to turn them for uniform crispness. Once golden and crunchy, remove them from the fryer and finish with a sprinkle of sea salt before serving.