Dramatic video has emerged of an NYPD captain being assaulted during clashes with looters that led to two arrests Tuesday night outside a Zara store in the Financial District, police said. The footage shows the police official wearing a helmet being shoved to the ground as two other cops in riot gear rush to his aid at the corner of Fulton Street and Broadway at 9:15 p.m. — more than an hour after a curfew went into effect. The officer in the white shirt then swings the helmet he lost in the scuffle at a man wearing a backpack, drops his helmet, punches the man and then grapples with him in the melee. Another officer then cuffs the man behind his back as he lies on the street. Juan Garcia, 21, and Fernando Lopez, 18, both of 60-61 Myrtle Ave., Queens, allegedly exited the closed store through a broken window after stealing merchandise, police said.