1. Heat the oven to 350°. In a large frying pan, cook the sausage over moderate heat, breaking it up with a fork or wooden spoon, until cooked through and just beginning to brown, about 10 minutes. Remove.
2. Pour off all but 1 tablespoon fat from the pan and reduce the heat to low. Add the beans and salt and cook, mashing the beans with the back of a wooden spoon, until heated through, 2 to 3 minutes. Most of the beans should be broken up, but don't mash them to a puree. Remove from the heat and stir in the sausage, half of the cheese, the tomato, lime juice, and onion.
3. Spread one quarter of the bean mixture in a line just below the center of each tortilla. Put the remaining cheese on top of the beans. Roll up the burritos and put them seam-side down in a small baking dish. Bake until the cheese is melted and the filling is hot, about 15 minutes. If the tops begin to brown too much, cover loosely with a sheet of aluminum foil. Serve the burritos with lime wedges.
Variation: Cut 1 pound of bacon crosswise into small strips. Fry until crisp and drain on paper towels. Proceed with the recipe from Step 2, substituting the bacon for the sausage.
Wine Recommendation: Hot Italian sausage, black beans, tomato, and cheese all argue for a big, fruity red wine. Find a robust zinfandel from California; its blackberry flavor and intriguing woodsy quality will stand up to, and enhance, this dish.