A Manhattan high school history teacher, who resigned under fire after taking students on a spring-break field trip to Cuba, is a self-proclaimed Communist who said he needed to see Fidel Castro one more time before the dictator died.

The shocking revelations are highlighted in a report released yesterday by the city’s special investigator for schools.

It’s recommendation bars Nathan Turner — who organized the April 2007 trip for himself and five students of the selective Beacon School on the Upper West Side — from working in city schools.

The report also exonerates the school’s principal, Ruth Lacey, said Richard Condon, the special commissioner who headed the three-year probe.

Turner, 39, who resigned in 2008, yesterday declined comment.