Not that difficult. Just use the traditional techniques for killing a vampire. Stake through the heart, decapitation, salt sewn in the mouth, grave facing the rising sun, etc. Bullets and knives will work temporarily, just make sure you butcher the carcass before they have a chance to regenerate from their injuries.
A bomb would work to kill them, but you're not going to get a lot of useful meat out of something that blows them into burned chunks.
Whatever method you use, do not try to poison them. These guys are accustomed to apocalyptic-grade drugs made from exotic substances. I saw a currency trader do a nine-foot rail of Nohl off the back of the human centipede at our Christmas party. Oh, what, you've never heard of Nohl? It's a Spetznaz combat drug that destroys the ego and makes you believe you are already dead. These guys do it to pep up for a Power Point presentation.
Before it's chow time you have to do the dirty work of butchering the Goldman Sachs executive. Begin by draining the blood. You can catch it for blood sausages or dispose of it in a ritual. Use a large, sharp blade and make clean cuts to open the abdomen and remove the heart, lungs, and assorted viscera. Try to minimize the cuts you make to the intestines so that you do not spill the contents of the bowels.
You can save the heart for black magic rituals. There is probably a tome containing several near where you found the executive. Look in the drawer marked with the pentagram. Try calling upon the many-faced benevolence of Mammon, if he is not busy with someone else.
Legs, shoulders, and arms all provide excellent cuts of meat. A decent anatomy book will tell you about the major muscle groups. The buttocks tend to be fattier, but are good for slow cooking or grilling. Adventurous foodies could have a real treat with the brains, marrow, tongue, and various organ cuts. These are high-protein, high-calorie, and nutritious. Be sure the brain is very thoroughly cooked to avoid cannibal encephalopothy. Since most Goldman executives are cannibals themselves there is a surprisingly high risk of contracting this disease.
The skin of the executive is not immediately edible. Lotions and tanning have done a number on the skin of most Goldman Sachs employees. Good luck finding someone above junior VP who doesn't have at least one melanoma you will need to cut out.
You will want to parboil the hide to clear out toxins from the pores and restore some flexibility. Cut the skin into three or four pieces as needed for the pots you are using. This process will also help loosen hairs and allow you to easily scrape out excess fat. About five minutes at a full boil should do it. Transfer the skin to drying racks to drip dry. After that, it is possible to tan the skin for belts, gloves, or shoes, but I prefer to make jerky. A Nesco Dehydrator works surprisingly well. You will probably have enough for more than one batch.
There is a saying, I think from the guys who run the Borgata: "Use every part of the Buffalo." That does not apply here. Throw away as much as you want. There are lots of Goldman executives. You can always get another one. Hell, we drive an aluminum truck around in a circle to make money speculating on the price of aluminum, so what do we care about the environment?
Fuck it, right? Anybody that matters will be living on the moon by the time I retire.
Apparently you do want to be lonely, because you defied the one rule of Farmers Only.
I highly recommend Windows 10 With Mouse + Keyboard Support Edition
The Something Awful front page news tackles anything both off and on the Internet. Mostly "on" though, as we're all incredible nerds.