They shoot with their eye, like in the first and second Heroes games, but judging by the screenshot, they shoot over one cell (or maybe it just seems that way), which means there will be no counterattack from enemies, and they respond with their hand (which is why they have such big hands) =)
Or is it an ability that can be used several times... and their main attack is melee? )
P.S. Also, they eat goblins and heal =))) conclusion from the interview I read.