Can you do it, assuming you haven't already resolved CF that round? I think you can--I don't see anything explicitly restricting resolving commands to the ship's activation (though of course most of them necessarily do happen during the ship's activation).
CF timing:
RRG pg 4 COMMANDS said:Concentrate Fire: Resolve during the “Resolve Attack Effects” step of an attack.
◊Dial: Add one attack die to the attack pool. That die must be of a color that is already in the attack pool.
◊Token: Reroll one attack die in the attack pool.
You definitely can't save a dial to do it with that later in the round, because:
Quote• After a ship finishes its activation, if it did not spend its command dial, that dial is discarded.
Edited by Ardaedhel
my quotes are bad and I should feel bad