All right, someone asked for an official "how-to."

Scalp wounds in the ER don't usually get lidocaine. Why? Well, you use a needle to put in the lidocaine... so you're being stuck anyway. Just stick them with the staple and be done with it. Yeah, I hear it hurts. People tend to jump. Clean the wound copiously with clean water (some people use a little betadine swirled in, YMMV). Pull the edges together so that the parts match up (kind of like matching up puzzle pieces - the indent in the skin on one side matches to the extra skin on the other) Staple it closed. The middle of the stapler is the centerline for the staple.

For non-scalp wounds, we usually take tweezers, grab the skin, and actually evert it, so that when the staple is in place, the skin "falls" back into alighnment, with just a touch of the edge still rolled up (I hope this is making sense). Leaves less of a scar, and it's a 2-person job.

Probably OK to use in the field, provided: A) you irrigate the heck out of the wound, and there's no visible debris. At least 1/2 liter. More if it's bigger. B) You staple far apart, about 1cm between staples. This allows the skin to still be open between the stitches, allowing a route for pus and stuff to egress. Of course, you can also pull the staples and re=clean the wound if you really need to. But at that point, you can't re-staple it closed.