Prepare the potatoes. Wash and scrub the potatoes thoroughly, then pat dry. Prick all over with a fork.
Microwave until tender. Place the potatoes on a microwave-safe plate and microwave on high for 8–10 minutes, turning halfway through, until beginning to soften. Cooking time may vary depending on the size of the potatoes and microwave wattage.
Crisp the skins. Preheat the air fryer to 200°C. Lightly rub the potatoes with the extra virgin olive oil and a small pinch of salt. Air fry for 8–10 minutes, or until the outside is golden and crisp and the centre is completely soft. Alternatively, finish in a hot oven for a little longer.
Make the filling. While the potatoes are crisping, add the drained tuna and sweetcorn to a mixing bowl. Add the red onion, red pepper, carrot and spring onions, followed by the mayonnaise, lemon juice and black pepper.
Mix together. Gently combine until the tuna is coated in the mayonnaise and the vegetables are evenly distributed, keeping plenty of texture and crunch.
Open the potatoes. Carefully slice a cross into the top of each cooked potato. Gently squeeze the sides to open them up, then fluff the inside with a fork.
Load them up. Divide the tuna, sweetcorn and crunchy veg filling generously between the two jacket potatoes.