It's a more nuanced question than "can the president pass legislation with an executive order?" The answer to that is no, of course. Not literal legislation.
However, the President can pass executive orders that fall under the authority already granted to him by Congress, which is a lot broader than most people think. As an example from my industry, the FAA has broad powers over our nation's airspace and the rules governing pilots, mechanics, airlines, etc. And highly independent authority - they don't need congressional approval to make changes to these regulations. Because Congress gave them that power, because Congress can't be arsed to sit down and look over every single little rule in the pilot's book. Few people in Congress would even understand the criteria for determining Decision Altitudes on an ILS approach, much less be able to make informed votes on changes to such a thing.
Since the FAA is an executive branch organization, Obama is in charge of the FAA. He could theoretically order the FAA to make regulatory changes - so long as those changes fall within the FAA's granted scope.
So the real question is, how broad is the authorization of ICE? How much power has Congress already granted the executive branch in this matter?
**** if I know, I'm not a lawyer.