After hitting just 3 of 16 3-point tries in their opening win over Bryant, the Irish knocked down 10 in the first half alone.
Matej Kavas scored 11 to pace Seattle (1-2). Redhawks leading scorer Brendan Westendorf, who came in averaging 19.5 points, did not score after missing all eight of his field-goal attempts, including seven from 3-point range.
He wasn't the only Redhawk who struggled as Seattle shot just 29 percent while committing 21 turnovers.
After being outrebounded by Bryant last Saturday, Notre Dame edged Seattle on the boards, 40-33, with Colson's eight leading the way.
Seattle: The Redhawks, who play all five of their Legends Classic contests on the road, faced Notre Dame for the first time. After playing Colorado tough in a 12-point loss in Boulder last week, this one got away from the Redhawks, who trailed by 20 with 6:25 still to play in the first half.
Notre Dame: Unselfish offense by the Irish continued to impress Wednesday night, dishing out 23 assists. The Irish are averaging 90.5 points after two games.
Seattle: Meets Louisiana-Monroe on Monday in the Legends Classic at Eastern Washington University in Cheney, Washington.
Notre Dame: Host to Loyola (Maryland) on Friday, its third straight home game to open the season before facing Colorado in the Legends Classic at Barclays Center in Brooklyn