Reheat the bread and let cool. Thinly slice the white cabbage. In a bowl, toss the cabbage with salt and sugar and knead for about 5 minutes. Then drizzle with a little vegetable oil. Cut the tomatoes into 5 mm slices. Cut the cucumber into 2 mm slices. Season both with salt and pepper. Cut the lettuce and onions into strips.
Shred the Smoked Tofu with a grater and sauté in oil until evenly crisp. Carefully slice open the pitas or flatbread halves to form pockets. Spoon in a little barbecue sauce. Fill the pockets with sliced lettuce, onion, white cabbage, tomato, and cucumber.
Add the sautéed shredded Smoked Tofu and top with the remaining barbecue sauce. Sprinkle with chilli flakes to taste. Serve immediately.