Whats the strongest form of encryption i can use for the wireless interfaces?

Thanks!

Using WPA preshared keys, the best is aes-ccm

And preferably a LONG password. Not "admin123" but for example: savWUJm";%H`bn9hp4mv

Try this site:

http://passwordsgenerator.net/

Select at least 20 characters or more. Since you are going to copy paste them into the Mikrotik, you can select the highest amount (I think it is 24 characters, but I might be wrong).