One of the weapons I came through with is called a zat'n'ktel, an alien device that is capable of disrupting mechanical devices. However, the first shot stuns, the second shot kills. (The third disintegrates, but I'm not sure that's needed here.) I also have a Wraith stunner, which knocks the target out for several hours and leaves them numb and immobile for several more.

I'm a very good shot with my projectile weapons as well, but if the goal is to disable rather than kill, one of those would be better to start with.