How do Dominion tournaments compensate for the luck that's always present in the game?
I don't think Dominion is alone in being a game with a significant amount of luck.  Magic the Gathering has a massive amount of variance, but the pros rise to the top time and again, because they are experts at keeping the role that luck plays in their game down to the very minimum.  Even with that being the case, I'd say that if you win 75% of your Magic matches at a pro level, your skill level is pretty godlike.  If you can consistently win even 60% of the time, you're doing more than fine.

As such, I don't think that it's a sensible question "how can we keep luck in Dominion to being a &lt;2% factor".  There's always going to be games of Dominion where you repeatedly draw exactly what you don't need and your opponent draws exactly what he does.  But if you don't let those games faze you, and just concentrate on outplaying your opponents, your win percentage should creep up comfortably above 50% as you become an expert at the finer point of the game.  And that's all it takes to be a great Dominion player.  Not 100% win rates against "lesser opponents" and the total elimination of luck, just the ability to maximise your game, whatever the game throws at you, and even though sometimes it won't be enough.