I've searched on some sites that follow anime and manga to see if the Japanese have a shortened name for it, but so far nothing came up. Since I needed to tag a question and it was late at night I settled on Denpa-Onna, but there are a few other works that have that in their name.
The generic advice for how to name series tags is here but most of those do not apply for this series.
Neither the English name "Ground Control to Psychoelectric Girl" nor the Japanese title "Denpa Onna to Seishun Otoko" fits without cutting something out. The English name would need to be trimmed to just psychoelectric-girl, which is probably not the best option. I tried a Google battle and "Denpa Onna" is 20 times as common as "Psychoelectric Girl", which I think is the sort of extreme case in which we should be using the Japanese name. Personally, I'd never even heard of the English name before looking for it.
I think the best option is probably denpa-onna-seishun-otoko which fits at 24 characters. We cut out the "to", in Japanese means "and", so there's basically no loss of information and all the keywords are present.