Chop the onion, zucchini and aubergine and fry. Add corn and kidney beans and let simmer in their own juice. Season well with chili powder, salt and pepper. Then add canned tomatoes and let simmer. Mix well with half a tube of tomato paste. Put the vegetable filling on the wheat flatbreads and roll up. Brush with crème fraîche. Finally sprinkle cheese over it and bake for about 13 minutes at 180 degrees.