Preheat the oven to 220C/425F/Gas 7.
Heat the olive oil in a 15cm/6in ovenproof frying pan over a medium heat. Add the potatoes and sauté for five minutes, or until golden all over.
Add the eggs and season with salt and freshly ground black pepper. Stir well and cook for one minute, then distribute the tuna and chives evenly over the pan.
Transfer to the oven and bake for five minutes, or until the eggs are completely cooked. Serve immediately.