That recusal cleared the way for the Assistant Attorney General to appoint Special Counsel Robert Mueller to investigate Russia/Trump after Trump fired FBI Director James Comey because the latter was also investigating the scandal. Trump expected all these people to be loyal to him and thus sandbag the investigation.
So Trump is now livid that the scandal investigation continues and he can't stop it. He's been openly criticizing Sessions, and Trump's attorney has admitted publicly the President wants him to step down (details here).
For his part, Sessions has made it clear he's not going anywhere (details here). And the Senate plans to avoid recessing indefinitly, so that Trump cannot fire Sessions and appoint an Attorney General who doesn't need confirmation (details here).
A President can normally approve cabinet secretaries for up to two years during a Senate recess and without a confirmation vote, which is known as a recess appointment. Without the power to replace Sessions, Trump now cannot stop the investigation.
I have to say I'm sort of amazed that no Republican has had the balls to publicly challenge Trump and ask -- "why do you want the Attorney General to step down other than to scuttle the investigation?" I'm sure many journalists have asked that of the White House press office, but of course they would not respond.
So all this has led to a stalemate between two odious individuals: the President and the Attorney General. The latter will continue his far-right conservative policies but he could also openly encourage further investigations into Trump's campaign, family, and personal business.
Like an idiot, Trump has turned one of his closest friends into a bitter enemy, and that bitter enemy happens to be the most powerful law enforcement officer in the country.
There's an old political rule that "the enemy of my enemy is my friend." So if Sessions is turning up the heat on criminal investigations into Trump, then more power to him, particularly if he shares the evidence with members of Congress who are also investigating the President.
Once again, Trump has proven to be his own worst enemy. He's a political neophyte who stupidly thinks he can out-maneuver an experienced political veteran.