Can counterattacking skills crit on their own?

If I attach an added lightning damage to reckoning, will it crit and shock if I have crit on me?

Yes.

The counterattacking skills (Vengeance, Riposte, Reckoning) are Attack skills. Attack skills always use your Weapon's base stats to determine the base amount of the Attack's Hit. There is currently no weapon that I know of that does not have Critical Strike Chance. Thus, all of the counterattacking skills should be able to crit just fine, so long as you don't have Resolute Technique allocated (which gives you the stat Never deal Critical Strikes).

Be aware that Shock can only apply on enemies if the Hit's Damage value passes the minimum duration threshold of 300 ms, which is 5% of their maximum Life without any duration bonuses. So you are unlikely to Shock anything but weak monsters if your only source of lightning is Added Lightning Damage and you do not have Elemental Damage bonuses.

Thanks adghar, although I thought shock always applies on crit?

Technically yes shock always applies on crit, but if the minimum duration of the shock isn't above 300MS the game ignores it and doesn't apply it.

I see. Cheers for that info, LightningStars. Switched from heavy strike to static strike to get some proper lightning damage in.