For junior I'd offer

* Watch them to solve a series of programming challanges. Offer them assistance if they ask. Let them search the net for assistance. Let them choose the language because your candidate will need to be able to learn on the fly anyway. Speaking of that...

* Don't neglect personality assessment, lots of tools out there to assess. Maybe your candidate should demonstrate a thirst for knowledge, history of independent learning, and some raw determination. Avoid hypothetical questions here and look for red flags that could make them suck to work with.

* Have them hang out with the team for a while, this could be during the code challange.

* Use the same process for all candidates