His ability says:

When attacking at range 2 or 3 you can spend an evade token to add 1 'hit' to your roll

In the rule book, it says that attack dice must be modified before defence dice are rolled, but only mentions target locks and focus tokens. Does this mean that this is when his ability has to take place in the usual order, or can you wait until after the defender has rolled to spend your evade to add a hit result?

Card says when he is attacking, so you use his power to use his evade token to add an extra hit to his attack die rolls during the attack die modification. Then the defender rolls his defense die and modifies them.

1. You declare an attack against an opponent's ship with Kir Kanos

2. You roll your attack dice

3. Opponent modifies your attack dice, if able

4. You modify your attack dice, if able (Kir Kanos' ability kicks in at this step)

5. Opponent rolls defense dice

6. You modify opponent's defense dice, if able

7. Opponent modifies defense dice, if able

If you killed off your opponent's ship and it doesn't have the same PS as Kir, great! Assuming this isn't during a simultaneous attack condition, then during the opponent's ship's attack, it can target your Kir Kanos ship sans evade token, if you spent it in step 4.

If it happened after defense dice it would say "after the defender has rolled defense dice" - this would have taken out all the risk associated with his ability, if the defender already rolled you would know whether spending the evade token was helpful or not. The whole point is "do I risk spending the evade for a hit or save it for defense?" - makes for a difficult decision sometimes since you don't know how your opponent will roll.