Preheat the grill and roast the peppers, turning until the skin starts to blacken on all sides.
Remove from the heat and put in a polythene bag to cool. Once cool, remove the skins and seeds.
Meanwhile, soak the preserved lemon in warm water for 5 minutes to remove the salt.
Peel the tomatoes, remove the seeds and juice, and cut the flesh into slices.
Cut the peppers into long slices and add the tomatoes and the preserved lemon, cut into tiny pieces. Dress with the oil and salt to taste.