Now all my ukes can hold a business card under the strings over the first fret without falling out. Typical recommendations I've seen from luthiers and building guides say that action at the 12th fret should be around .090" for a tenor, but personally I find that WAY to high. As long as your uke has a straight neck, you should be able to get that down to .030" or better.
See, when there's a holiday, I get to hang out on UU.
Its threads and responses like these that are worth taking some time to respond to.
First of all, and we are talking Tenors, if you have your action set at the nut to where a it can hold a business card without falling out, and your string height over the 12th fret is .030", then you are definitely buzzing all over the place, unless you have steel strings, with extremely high tension, in which case you wouldn't be playing because your bridge popped (unless its pinned) or your soundboard caved in (unless you're playing a low end, overbuilt instrument, or a high end instrument built for steel).
Getting back to the thread, there's a difference between high tension strings and how they feel, and high action. High tension strings don't necessarily make an instrument harder to play, nor does normal tension strings make it easier to play. I'm not sure which one are you concerned/asking about (because the title says "tension", but the post mentions "action"?
Taking a stab:
You can affect action with different tension strings.
Given the same action, higher tension strings will feel stiffer.
Personally, I can get the action lower with higher tension strings, comfortably down to about .100" over the 12th. Normals I usually leave at .105" or more, but I normally don't do normal.
What you probably need is for your instrument to be set up, which, all instruments should be. Outside of customs, a good setup will probably run you $50 give or take, depends on if you get your frets dressed or not.
Just my $.02 - Aaron