Returning to academia after a year in industry I need an advice about returning to academia as a visitor/post-doc after working for a year in finance.

I finished my PhD in summer 2013 with a good record of publications (3 papers in high impact journals). Both my bachelor and PhD were in applied mathematics and theoretical physics. Towards the end of my PhD I felt burned out and was unsure if I want to continue the same line of research.

Furthermore, almost all my colleagues who finished their PhDs around the same time struggled to find positions and all moved overseas, which was not an option for me at that time.

During this time a have kept in touch with my supervisor and colleagues. I also kept reading and searching for new interesting ideas. Recently I started to feel enthusiastic again and full of fresh ideas.

My question is do you think it is acceptable to approach my supervisor/colleagues and ask for a position and what is the best way to go about this?
Sure, why not? What you write makes me think that you could tell them exactly the way you tell it here: Being recovered from the PhD and full of fresh ideas.

It is not unheard of that PhD students need to recover from the PhD by doing some different kind of work for a while (such as a couple of years in industry, I've even heard of running a store in a completely different retail sector).
Personally, I think that it should be taken as a warning sign if this happens regularly. However, that consideration doesn't have anything to do with your position, but I think it is worth while remembering when you enter the side of PhD supervisors. 

Regardless of how much enthusiasm you've gained back I think it would be a good idea to sit down and recall what exactly drove you away and what caused you feel (close to) burned out - in order to avoid getting there again. I somehow think it unlikely that a postdoc position would be more calm than a PhD.