Ingredients

• 4 ounces thin bean thread noodles
• 1/4 cup dried arame (seaweed)
• 3 tablespoons unseasoned rice vinegar
• 3 tablespoons white soy sauce
• 2 tablespoons mirin
• 2 teaspoons fresh lemon juice
• 1 1/2 teaspoons finely grated green chile (such as serrano)
• 1 teaspoon toasted sesame oil
• 1 firm green pear, cut into matchsticks
• 1/2 small sweet onion, cut lengthwise into quarters, thinly sliced crosswise
• 12 ounces yellowtail, cut into 1/2-inch pieces
• 1/2 cup torn mint leaves
• 2 tablespoons finely chopped chives
• 2 teaspoons toasted white and/or black sesame seeds, plus more for serving
• Kosher salt
• Gochugaru (coarse Korean hot pepper powder) or crushed red pepper flakes (for serving)

Instructions

1. Place noodles in a large bowl and pour boiling water over to cover. Let noodles soak until tender but not mushy, 10–15 minutes; drain. Rinse under cold water; snip into 2" lengths with kitchen shears and return to bowl.
2. Meanwhile, soak arame in 1/2 cup cold water in a small bowl until softened, 8–10 minutes. Drain; set aside.
3. Whisk vinegar, soy sauce, mirin, lemon juice, chile, and oil in a large bowl. Transfer ⅓ cup lemon-chile shoyu to bowl with noodles and toss to coat. Add pear, sweet onion, yellowtail, mint, chives, reserved arame, and 2 tsp. sesame seeds to remaining shoyu in large bowl and gently toss; season with salt.
4. Divide noodles among bowls and top with yellowtail mixture; sprinkle with gochugaru and more sesame seeds.
5. Shoyu can be made 1 day ahead. Cover and chill.