A Long Island man who tearfully pleaded with the public for two days to help him find his missing wife admitted in court yesterday that he killed her.

William Walsh, 31, pleaded guilty in Nassau County Court in Mineola to murder, evidence-tampering and weapon-possession charges.

He said he strangled special-ed teacher Leah Walsh, 29, during a fight in their Bethpage home after returning from a trip to Atlantic City in October 2008.

Her body was found 50 feet off a Long Island Expressway service road.

Walsh could get 18 years to life in prison when he is sentenced on June 23.