That church directly across the Grand Canal from the train station with the green oxidized dome and Neoclassical facade is the San Simeon Piccolo, rebuilt in 1718–38 by Giovanni Scalfarotto (in a vague imitation of Rome's Pantheon) on the site of a 9th-century church.
San Simeon Piccolo (technically named SS. Simeon e Giuda) is actually rather unimportant as far as Venice churches go, but it is most people's first view of Venice