Title says all; are you able to crit with Struggle? It's not technically a move…
Yes! Struggle may be an exaggeration move that only deals damage when out of PP, but all moves have a probability of critical hits. Since the user is forced to use it, it does 50 damage (base powered), and that's it (while hurting himself in the process). But, the user is still alive, therefore it is still capable of a critical hit.
Hope I helped! :)