... and can the police officer who LIED (perjured himself) when saying the sandwich "exploded all over" be privately charged if the court won't do it themselves?

Who knows but if he does they should bar the agent and lawyer that brought up the charges from ever bringing charges again on anybody.

He probably can't. Absurd as it may sound, he was actually guilty.

Here are model jury instructions for the charge, which include:

There is a forcible assault when one person intentionally strikes another

It doesn't say that the victim must be struck with something very likely to injure them. Looking at the statute, it turns out that actual physical contact (rather than making a threat without contact) elevates it to a felony - the charge a grand jury previously rejected.

Of course, prosecutors normally apply common sense to charging decisions and don't prosecute everything that technically qualifies under the strictest reading of a statute.

No, he sues for damages. Time lost, mental anguish, etc

Sue for delicious prosecution I say