Make the peppercorn mixture: Heat 2 tablespoons oil and half of the freshly ground peppercorns in a medium skillet over medium-low heat. Cook, stirring frequently, until fragrant, about 1 minute.
3 Tbsps olive oil, 1 tsp freshly ground peppercorns
Add the aromatics: Add the garlic, sriracha, ginger and scallions. Cook, stirring constantly, for about 1 minute, just until fragrant. Remove from the heat and set aside.
4 cloves garlic, ½ Tbsp sriracha, 1 inch fresh ginger, 3 scallions
Prepare the broiler: Position an oven rack as close to the broiler as possible and preheat the broiler to high.
Season the green beans: Place the green beans in a large bowl and toss with the remaining 1 tablespoon oil. Season with kosher salt and the remaining freshly ground peppercorns.
1 pound fresh green beans, Kosher salt
Broil the beans: Arrange the green beans in a single layer on a foil-lined baking sheet. Broil for 3–5 minutes, watching closely, until the beans are blistered, tender-crisp and lightly charred in spots.
Toss with the sauce: Return the hot green beans to the bowl. Add half of the garlic-peppercorn mixture and toss well to coat.
Finish and serve: Transfer the green beans to a serving dish and spoon the remaining garlic-peppercorn mixture over the top. Taste and add additional salt, if needed. Serve immediately.