President Obama should pardon illegal immigrants known as the Dreamers. In fact He should pardon all 11 million or so undocumented immigrants.
This would NOT make them citizens. It would however allow them to stay in the United States without fear of deportation.
It is His presidential privilege to do so. It is guaranteed under the Constitution of the United States. It is the easiest, fastest, fairest, cheapest and best way to handle this problem. At least I think so.
President Ford pardoned President Nixon for Watergate.