Well from what I can see, Love seems to be a noun. Thus
Amor supra omnia.
Literally "Love above/beyond all things".
But as a verb, to me it would mean something like, "Above all, love" as you said. It would be translated into Latin as a command. So it would take the imperative.
Supra omnia, ama/amate. (Ama if you are taking to a single person, amate if you are talking to many. Since it is a tatoo, go with amate.)
Literally "Above all, love"
While in English it may be hard to make the distinction between the phrase using a noun vs a verb, in Latin there is no mistaking.
One could also translate "Above all, love" into "Above all, you must love". In Latin that would be
Supra omnia, vobis amandum est.
Which ever one you pick is up to your own preference of what you are trying to say.
And yes it would be different to use the noun vs the verb. If you use the noun it shows that
love is above all things. But to use the verb is to tell someone to love as the utmost importance.