Add the trimmed beans into the water and cook for 1-2 minutes.
Drain the hot water from the beans and place the beans into an ice water bath.
When the beans are no longer warm, remove the beans and drain well, patting dry with paper towel.
In a small bowl, combine white miso paste, Chinese sesame paste (or tahini) and mix well. Add in a few tablespoons of hot water to thin out the mixture. Set aside.
In a frying pan over medium heat, add in 1 teaspoon of sesame oil and minced garlic.
Sauté the garlic for about 1 minute, until slightly fragrant.
Add in the green beans and lightly toss to coat.
Remove from heat.
Drizzle the sesame miso sauce over the beans, toss lightly, sprinkle with sesame seeds (if using) and serve.