NEW YORK — The Queens District Attorney’s office was aiming at the accused “Duck Sauce Killer” when targeting his wife for gun possession, her attorney suggested in a pointed letter to prosecutors. Defense lawyer Mark Bederow, in his Tuesday missive, questioned whether 62-year-old Dorothy Hirsch was arrested in hopes of flipping her to testify against spouse Glenn Hirsch in the April 30 slaying of beloved Chinese restaurant deliveryman Zhiwen Yan. “We are deeply concerned that your office is abusing various provisions of the penal law and criminal procedure law in hopes of ‘squeezing’ Ms. Hirs…