FLUSHING, Queens (PIX11) -- A man threatened two 13-year-old kids with a machete-like knife and tied their hands together with a shoelace before raping the young girl in a Queens park on Thursday, authorities said. "This incident is a parent's nightmare," NYPD Chief of Department Jeffrey Maddrey said at a press briefing Friday. The suspect approached the teens on a field in Kissena Park near Colden Street and Kalmia Avenue at around 3 p.m. and…