1 pound green beans, trimmed
2 teaspoons rice vinegar
1/2 teaspoon toasted sesame oil
Coarse salt and ground pepper
1 teaspoon sesame seeds
Set a steamer basket in a large pot. Fill with enough water to come just below basket; bring to a boil. Add green beans to basket; reduce heat to a simmer. Cover, and cook until crisp-tender, 15 to 20 minutes.
Meanwhile, in a medium bowl, whisk together vinegar and oil; season with salt and pepper. Add green beans and sesame seeds; season with salt and pepper, and toss.