Prep the noodles: Cook noodles according to package directions until just tender. Rinse briefly under cool water to stop the cooking, drain well, and toss with a drizzle of sesame oil to prevent sticking.
Make the meatball mix: In a large bowl, combine ground pork, egg, panko, garlic, grated ginger, scallion whites, 1 tablespoon soy sauce, and 1 teaspoon sesame oil.
Mix gently with a fork or your hands until just combined. Don’t overmix.
Form the meatballs: Roll into bite-size balls, about 1 to 1.5 inches in diameter. You should get 18–24 meatballs.
Place on a plate or tray.
Sear the meatballs: Heat 1–2 tablespoons neutral oil in a large nonstick skillet over medium-high. Add meatballs in a single layer without crowding. Sear, turning every 1–2 minutes, until browned on most sides, about 6–8 minutes total.
Build the sauce: Lower heat to medium.
In a small bowl, whisk 1/2 cup sweet chilli sauce, 2 tablespoons soy sauce, 1 tablespoon fish sauce (if using), and 1 tablespoon rice vinegar or lime juice. Pour into the pan with 1–2 tablespoons water.
Glaze and finish: Toss meatballs in the sauce and simmer 3–4 minutes, until the sauce is sticky and the meatballs are cooked through (internal temp 160°F/71°C). If the sauce reduces too quickly, add a splash of water.
Taste and adjust with more lime or soy.
Prep the vegetables: While the meatballs cook, slice cucumber, carrot, and red pepper. Roughly chop herbs. Keep them crisp and fresh for contrast.
Assemble the bowls: Divide noodles among bowls.
Spoon over meatballs and glossy sauce. Add vegetables and herbs. Sprinkle scallion greens, sesame seeds or peanuts, and chilli if you like heat.
Serve with lime wedges and extra sweet chilli sauce.