Slice the sausage and brown in in a large pan.  Drain the salsa, reserving the juice in a small bowl (you want about 1/3 of a cup, discard any more than that).  Add the beans and corn to the pan.  Whisk the flour into the reserved salsa juice.Add salsa juice/flour to pan, and stir until thickened.  Voila–you're done!  Serve with grated cheddar on top.