Lime slices CUT EACH SAUSAGE INTO 4 PIECES. Place in a 3-quart pot, place over medium heat on the stove and cook, 5 minutes. Pour off and discard fat and reserve the sausages on a plate. Add the onions and cook, stirring occasionally, 5 minutes, or until the onion softens. Halve tomatoes crosswise, lay each half cut side down and cut each half into 6ths. Add the tomatoes and tomato paste to the pot and cook, stirring, 2 minutes. Add the hominy, oregano, salt, pepper and hominy water. Cover, raise heat to high, and bring to a boil. Lower heat to medium and simmer 20 minutes. When it's time to get dinner on the table, replace the sausages in the pot and cook 7 minutes. Remove from the heat and add the parsley. Divide the ingredients between 4 soup bowls and garnish with lime slices. Serve warm tortillas instead of bread.