Can you use 2 focus on 1 attack (if you have recon) or is it 1nce per attack?

It is once per attack.

If you have multiple focus tokens, you can use it on each attack.

Can you use 2 focus on 1 attack (if you have recon) or is it 1nce per attack?

It is once per attack.

If you have multiple focus tokens, you can use it on each attack.

The basic use of Focus tokens, "change all [eye] results to [boom] results" is once per attack, yes (although outside of a very few corner cases you wouldn't want to use it more than once per attack because the second token would be wasted).

If you have another way to spend Focus during an attack (Weapons Guidance, Calculation, Deadeye...) then you can certainly spend one for the regular effect and one for the other effect (you may need to do it in the other order).

In general, things can only trigger once per opportunity you have to trigger them. So you get the opportunity to trigger Kanan's pilot ability each time you are attacked, and you can resolve it once each time you are attacked, removing one die from the attacker by spending a focus token.

Edit: I didn't see the topic when I wrote this answer, so I was answering the question I thought had been asked (a general "can you spend two focus tokens on an attack?", not the one that was actually asked. Sorry about that, folks.

Can you use 2 focus on 1 attack (if you have recon) or is it 1nce per attack?

It is once per attack.

If you have multiple focus tokens, you can use it on each attack.

The basic use of Focus tokens, "change all [eye] results to [boom] results" is once per attack, yes (although outside of a very few corner cases you wouldn't want to use it more than once per attack because the second token would be wasted).

If you have another way to spend Focus during an attack (Weapons Guidance, Calculation, Deadeye...) then you can certainly spend one for the regular effect and one for the other effect (you may need to do it in the other order).

Basic use of focus to change focus results to Hit results is not once per attack. But all card abilities are.