Rinse the green beans, trim off the stem ends (and any stringy bits). Bring a large pot of salted water (use the 1 tsp kosher salt) to a rolling boil. Add the green beans and blanch until bright green and just tender-crisp, about 2–3 minutes depending on thickness.

Prepare an ice bath (the 2 cups ice water). Immediately remove the green beans with a slotted spoon or drain and plunge them into the ice water to stop cooking. Leave in the ice bath for 2 minutes, then drain thoroughly and pat dry on a clean kitchen towel or paper towels.

Sauce

Mix sauce

In a small bowl, whisk together the dark sweet soy sauce (2 tbsp), light soy sauce (1 tbsp), rice vinegar (1 tsp), sugar (1 tsp), and 2 tbsp water until the sugar dissolves. Set aside.

Aromatics & Stir-fry

Heat wok

Place a wok or large heavy skillet over high heat until very hot (smoking slightly). Add the neutral oil (2 tbsp) and swirl to coat.

Add the sliced garlic and julienned ginger, stirring constantly for about 15–20 seconds until fragrant but not browned. Watch closely to avoid burning.

Add the blanched, dried green beans to the wok and spread them into a single layer as much as possible. Let them sear undisturbed for 30–45 seconds to get some blistering, then toss or stir-fry aggressively for 1–2 minutes until they develop char spots and are heated through.

Pour the prepared sauce over the green beans and continue to toss for 30–45 seconds so the sauce coats the beans and thickens slightly. If needed, raise the heat to reduce the sauce further; be careful to avoid burning the sugar in the sweet soy.

Turn off the heat and drizzle the toasted sesame oil (1 tsp) over the beans. Add the sliced scallion greens (3 each) and freshly ground black pepper (1 tsp). Toss to combine.

Transfer to a serving dish and sprinkle the sesame seeds (1 tsp, optional) on top. Taste and adjust seasoning if needed (add a pinch of salt or a splash of light soy if you want more saltiness). Serve immediately.