Forget the veins, how about slowly cooking him to death like the French use to do to Islamic assassins in the early 1800s? Tie him to a tree and start with the arm, slow cook it down to the bone, keep going to the other arm then legs, then if he’s still alive impale him through the butt. That’s what they did to the assassin of General Jean Kleber in 1800.
http://en.wikipedia.org/wiki/Jean_Baptiste_Kl%C3%A9ber
Durn! What did they do when they were mad?