Why do you think the Democrats are so hot to appoint a special prosecutor over a non-crime? A special prosecutor will have subpoena powers to ask Trump for any document including his tax records.
Trump was right to be mad at Sessions for recusing himself and the Republicans should fight any attempt for a special prosecutor. It's only a fishing expedition.
There is more than one pond to fish in. How about a little fishing in the 0vomit pond. And the Clinton pond.