Goals from Andreas Weimann and Charles N'Zogbia set up the victory for Paul Lambert's men, who enjoyed the better of the contest.
The win was their second of the close-season having overcome Mansfield Town 3-1 on July 17.
Villa take on the Houston Dynamo on Saturday before heading back to Europe to complete their Premier League preparations.
The teams took a while to settle before Irishman Enda Stevens almost gave Villa a 30th-minute lead.
Dallas defenders backed off the 24-year-old, who moved to the edge of the area before having his left-footed strike palmed away by goalkeeper Raul Fernandez.
Andres Escobar, on loan from Dynamo Kiev, had a glorious chance to put Dallas ahead soon after, but he skied an opportunity well over.
Dallas would be punished just before half-time.
Darren Bent broke forward down the right before squaring for Weimann, who fired in despite Fernandez getting a hand on the strike.
It continued a bright pre-season for Bent after the striker also scored a brace in the win over Mansfield Town.
Lambert made 11 changes at the break and Villa doubled their lead in the 49th minute, when N'Zogbia struck with a free-kick.
Villa looked largely untroubled by Dallas, who sit second in the Western Conference in MLS, as they saw out a relatively comfortable win.
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