In the USA, when someone accuses someone else of something, does the accused have the right to face his/her accuser?

Yes, a defendant has the right to face the accuser, and the defendant’s lawyer may question the accuser.

Although what @zenvelo says is technically true, the process is riddled with exceptions and escape hatches, and (depending on he situation) the accused may or may not face the accuser.

With social media, people are accused of things all the time and there’s little or no recourse.

You didn’t mention if you are referring to a crime, or something else, @luigirovatti.

@jca2: Yes, I’m referring to the police making the accused and the accuser compare each other.

If it’s a crime, the prosecutor prosecutes it (meaning the District Attorney) and the defendant has his day in court to defend himself.

@luigirovatti that won’t happen at the police station. Only when it goes to court.

The police are not trained to deal with that sort of confrontation.

Yes, absolutely. However, in a criminal case the victim (or alleged victim) is not the accuser – the state, via the prosecutor (aka state’s/district attorney) is. The victim comes to the police to report a crime against them. The police investigates, gathers what evidence they can and, when they feel the evidence is sufficient, then presents the evidence to the prosecutor. The prosecutor then considers the evidence and decides if it’s substantial enough to file criminal charges. If criminal charges are filed then that is the accusation, the prosecutor is the accuser and the defendant has the right to face the accuser and challenge the accusation in a court of law. The victim themselves might not ever even set foot inside the courtroom.

In a civil case, where one party files a law suit against another, the suing party is the accuser. In such cases the lawsuit will be thrown out by the court if the suing party fails to appear in court.

Yes, in a court of law.