This is basically papercraft transported to a different medium, im using maculas imp template, the simplicity of the design is really hard to beat.
print off the template and trace it onto your can.
cut it out (im using utility scissors designed to cut through anything, you could use tin snips or just an old pair of scissors you don't mind blunting).
copy the lines from the template onto the body
this'll be what the other side looks like, well, not really, not unless you're using the same type of can and placed your template in exactly the same place, should be the same shape though, if its not you suck
use a straight edge to fold along the lines, bare in mind that the metal's pretty thin, don't score the lines or the section'll probly just fall off.
using a decent super glue designed for metal, glue the side tab to the body then close the top and glue it. i scratch the tabs up a bit to give the glue a better purchase.
leave it to set.
same again for the head
before you seal him up, you'll wanna give him a face, on this first one i just drilled it
fold it all up and glue it then just follow the same steps for the arms
stick it all together, easy as.
there's more of the models i've made and things i've tried like poseable arms/head,glowing eyes on my blog.
i know this aint the best how-to so feel free to ask me anything.