I already submitted my application and they are about to start interviews, however learning more about the faculty I found a potential supervisor and I would like to know whether there are chances they are interested in having me doing that kind of research (understanding whether he will accept supervisees or other colleagues that have same interests will).
I wouldn't recommend it. Standards vary but from my experience, it can be seen as trying to influence your chance of admission.
Generally speaking, if you want to contact faculty before getting accepted, the appropriate time to contact them is before submitting your application (and even then, it's not uncommon to be turned down).
Again, standards vary and I'm sure some faculty are fine with it, but the general impression I've gotten (at least in US universities) is that it's often considered inappropriate during the admissions process and you should wait until a decision is made.