Blanch tomatoes for a few seconds in a pot of boiling salted water, drain, rinse with cold water, drain again, peel, quarter and remove seeds. Rinse scallions, trim and chop. Heat oil in a pan and fry chicken cubes for about 5 minutes and season with cumin, paprika, salt and pepper. Add scallions and tomatoes, fry briefly while stirring and season to taste with salt and pepper. Drain and absorb broth.
Spread tortillas with about 1 tablespoon of sour cream each, cover with chicken mixture, roll up and place in a greased casserole dish. Cover with cheese. Bake in a preheated 200°C (approximately 400°F) oven for about 15 minutes.
Serve with strips of iceberg lettuce and tomato quarters.