What key is used for Target Lock? (And any other useful keys?)

[An Ning]

there is nothing in the menu to tell you and I am completely tired of having to guess if I am lining up right in these dang duel sequences where you can't move the camera to see.

Is there a target lock key available? And if so, what key is it?
(Also, are there any other useful keys that exist but we are left to divine via the Force?)

[FJI Javi 13]

Target lock = ctrl