Mix together thoroughly the ground beef, ground pork, rice, egg, and half of the onion, salt, pepper and paprika, plus 1/4 cup of the tomato sauce in a large mixing bowl and set aside.
Mix together the rest of the tomato sauce, onions, salt black pepper and paprika with the diced tomatoes and set aside.
Cut out center core of cabbage. Put in large pot of boiling water, Carefully and slowly flake away each large leaf with the handle of a wooden spoon. After every four or five leaves are flaked away, let them cook in pot for about 3 min. till wilted.
After separating and wilting cabbage, let leaves cool, then trim down the protruding center (nose) of each leaf to make it easier to roll. Put approximately 5-6 tablespoons (about the size of a small child's fist) of the meat mixture onto each leaf, roll, and tuck in both ends with forefinger.
Line the bottom of large pot with chopped cabbage leaves and some of the sauerkraut. Place some cabbage rolls snugly in bottom of pot.
Pour over them some of the seasoning mixture from the small bowl and some sauerkraut. Add another layer of cabbage rolls and repeat till rolls and seasoning are used up.
Add enough water (or you can add some tomato juice) to bring the liquid at least as high as the rolls in pot. Cover and cook on low for about 30-45 min. or when rice is done.