Heat the oven to 200°C (400°F, gas mark 6). Place the peppers closely together, cut side up, in an ovenproof dish and bake for 20 minutes, or until softened. Remove from the oven and set aside.
Meanwhile, heat 2 teaspoons of oil from the jar of sun-dried tomatoes in a large nonstick saucepan and sauté the onions for 5 minutes, or until softened. Add the garlic and sun-dried tomatoes and continue cooking for a further 2 minutes, then stir in the rice.
Pour the stock or water and wine into the rice mixture, stir well and bring to the boil. Cover and simmer for 15-20 minutes until the liquid has been absorbed and the rice is tender. Add a little more water if the rice dries out during cooking.
Meanwhile, cover the tomatoes with boiling water, leave for 1 minute, then skin, deseed and chop them. Add them to the cooked rice mixture with the olives, spring onions, pine nuts and mint, season well and stir to combine. Spoon the rice into the peppers and sprinkle the feta cheese over the top.
Return the peppers to the top shelf of the oven and cook for a further 15 minutes, then serve.