Get the rice noodles cooking 1 minute less than package directions. Drain, quick cold rinse, drizzle with a tiny bit of oil. Set aside.
While the water boils, heat a large skillet or wok over medium-high. Add oil/butter, season shrimp lightly, and sauté 1–2 minutes per side until just pink. Scoop them out.
Same pan — no need to clean — dump in your 1½–2 cups of leftover soup, peanut butter, soy sauce, brown sugar, ginger, and sriracha. Whisk until the peanut butter melts and everything looks smooth (3–4 minutes).
Taste it! Too thick? Start adding hot pasta water or milk a splash at a time. Need salt? More soy. Need heat? More sriracha. Need life? Big squeeze of lime.
Toss in the frozen peas — they’ll thaw instantly. Add the noodles and shrimp back in. Gently toss until every noodle is coated and everything is hot. If it tightens up, keep adding liquid until it’s saucy but not soupy.
Off the heat, throw in a big handful of torn herbs. Serve in deep bowls piled high with peanuts, green onions, more herbs, and lime wedges.