Sure enough, there's a small, swooping triangular space at the far western end of Canal Street, just across the West Side Highway from the Hudson River, and that's Canal Park.
The building that houses the brand-new theater dates from 1826, which seems old enough, but according to signage the park is in some sense 140 years older than that, set aside as a public space by the 1686 Dongan Charter – though the Parks Department web page gives 1833 as the date the site was established. It's unclear to me what the Dongan Charter, which established Albany as a city in 1686, has to do with this site, though the Charter is interesting enough, being, according to the Albany Times Union, "[t]he oldest city charter in force in the United States [and] arguably the longest-running instrument of municipal government in the Western Hemisphere."
Whatever its true age, Canal Park has an interesting history: originally a marketplace, then a park, later redesigned by Calvert Vaux and Samuel Parsons, Jr., then decommissioned, then used as a Sanitation Department parking lot, then researched and restored as a park in 2005 with inspiration from the Vaux design. Deserted (except for pigeons) on a chilly, sunny February day, it speaks its chapter of history to anyone who takes the trouble to listen. And, yes, I can envision the Canal Park Playhouse folks sitting out here with lunch and a cigarette during a long day of rehearsal as soon as springtime comes around.