If a player roll a 12 while trying to MC someone does the target take a click of damage?

No. Mind Control causes no damage, as opposed to Incapacitate which causes zero damage. Since MC does not cause any damage at all, a critical hit won't add anything to it.

Also if you roll a critical miss your figure won't take damage either.

this has been probably been asked before.....
can you mastermind mind control damge.....the damage you get for MC'ing 100+ pt figs....

No. A character *takes* Mind Control feedback damage. Master Mind works on damage *dealt* to the character. There is a very significant difference between damage *taken* and damage *dealt*.