In a medium bowl, whisk together the peanut butter, soy sauce, rice vinegar, sesame oil, sriracha, lime juice, ginger, garlic, brown sugar, and red pepper flakes until smooth and well combined. Taste and adjust seasoning with salt as needed. I find that letting this sauce sit for a few minutes allows the flavors to meld together beautifully, creating a more balanced and complex taste.

Bring a large pot of salted water to a boil and cook the linguine according to package directions until al dente. Drain the pasta thoroughly, then rinse it under cold running water until completely cooled to prevent it from sticking together and to stop the cooking process.

While the pasta cooks, julienne the carrots, slice the cucumbers into thin rounds, and thinly slice both the red and yellow bell peppers. Slice the green onions on a bias into 1/4-inch pieces. I like to keep the vegetables separately until combining them with the pasta so they stay crisp and vibrant rather than releasing excess moisture too early.

In a large mixing bowl, combine the cooled pasta from Step 2 with all the prepared vegetables from Step 3. Pour the peanut sauce from Step 1 over the mixture and toss everything together thoroughly until all the pasta and vegetables are evenly coated with the sauce. The sauce will cling beautifully to the noodles and vegetables, creating a cohesive dish.

Cover the bowl and refrigerate the pasta salad for at least 1 hour to allow the flavors to meld and develop. Just before serving, give the salad a quick stir to redistribute the sauce (it settles as it chills), then transfer to a serving dish. Top with the chopped fresh cilantro and roughly chopped peanuts for a fresh herbal note and satisfying crunch that contrasts beautifully with the creamy noodles.