I gave his full name in the correct order (Rannadril Ghan Swa Fulsoom Cetoo Tal Jaerdi).

But he most often works for people who use the form [given name] [family/clan name] and so usually introduces himself (and thinks of himself) under that order.

In fact, it seems Salarians generally only introduce themselves with their given name, often not telling anyone any of the rest, not even their clan name. For formality, I think Mr. [given name] would be just fine, as if one is bothering to include Tal in a formal adress one may as well use the whole lot. To a Salarian, all the extra parts of their name are only really important to other Salarians for the purpose of determining genetic stock.