In a large saute pan that has a lid, heat the oil over medium-high heat. While your pan is heating, snip the ends off your beans. (I just snip off the end that was attached to the plant - you do what works for you.) When your pan is hot, add the beans. Don't stir, just let them sit for a little bit.

After a few minutes, give the beans a good stir. You'll probably see a few charred spots on the parts that were touching the pan - this is what you want. Let them sit a minute or two longer, then stir again, letting the beans get charred in a few more spots.

Turn the heat down to low and cover. This is where the magic happens! Let the beans steam for 20 minutes or so, stirring every 5-ish minutes. Don't worry too much about them, though - they'll be fine.

Once your beans are done to your liking, uncover, crank the heat up to high. Once your pan is hot (your beans will probably be sizzling), add in the splash of vinegar and let it reduce. Season to taste with salt and enjoy!