Kyle Steyn scored four tries while his fellow Glasgow Warriors wing, Rufus McLean, enjoyed a debut double in the opening 15 minutes, with Edinburgh loosehead prop Pierre Schoeman also marking his first international cap with a try on the half-hour mark.
There were further second-half scores from hooker George Turner and substitute duo Nick Haining and Oli Kebble.
Number 10 Blair Kinghorn contributed with three of his seven conversion attempts, while debutant replacement Ross Thompson successfully kicked two of his three efforts as Gregor Townsend's side made the most of their first match in front of supporters since March 2020.
Tonga have been hampered by unavailability and lack of preparation time but they showed in glimpses what they can do with James Faiva kicking three penalties and David Lolohea going over from close range for a try.