19th annual season of free performances by Young Dancemakers Company, directed by Alice Teirstein and music director William Catanzaro.   Sixteen talented teens, selected by auditions in NYC public high schools, will choreograph and perform their own works, showing a range of themes, music choices, and dance styles, and will also dance an excerpt from Paul Taylor's "Esplanade," taught to them by Richard Chen See.   All performances end with "Dance With Us," with the audience invited on stage to improvise with the company.