As best as possible, I think a company should screen for that in the Interviews.  (given that Interviews are sometimes a effectiveness gamble, I realize that it can be difficult to screen for that).  I usually watch to see if they light up and get into conversations when I ask questions in the Interview related to our tech.  If they don't get that expression and interest (hard to qualify but I think most people know what I am talking about) than that is a lot of hire points lost.  If you spend an hour talking computers and they never 'light up', I feel, they are probably not the right fit.