Most of the "small percentage" of Americans employing the several million illegal aliens here, are the people who grow your food, and provide all manner of manual labor. Go ahead and slap 'em down if you want. But understand that you may not enjoy the consequences of putting those folks out of business.
I think it's better to get more positive control over the folks who do come here to work (i.e., the "guest worker" idea, with appropriate safeguards); than to treat the problem with the same notable success we've had with the War On Drugs (which uses, BTW, the same tactics suggested by so many on this and similar threads).