Bring a large pot of water generously seasoned with salt to a boil over a medium-high heat.
Add the green beans and blanch for 2 minutes.
Transfer to an ice bath to stop the cooking, then drain.
Heat the butter or ghee in a sauté pan over a medium-high heat.
Once hot, add the garlic and cook until fragrant, about 30 seconds.
Add the green beans, coconut aminos, rice vinegar, and sesame oil (if using), toss to coat.
Season to taste with salt.
Cook for 3-5 minutes, stirring frequently, until the sauce has reduced and the green beans are just starting to get tender.
Transfer to a serving bowl, drizzle the remaining sauce over the green beans and serve hot.