This line is Jewish and immigrated to New York from the border of Poland and the Ukraine in the late 1800's.
Pensak - I looked in a Polish dictionary; might it be related to panski, meaning "nobleman"?
Spitz
Greenberg - pretty obvious, "green mountain"?
Sisselman - related to Solomon, by chance?
Pachomitsky (sp?) - only had an old handwritten paper to go by
Kalnitsky (probably) - same as above
Breines