Cook the noodles in salted water according to package directions until they are al dente.
Meanwhile, in a large measuring cup, whisk together the soy sauce, sriracha, lime juice, maple syrup, and sesame oil and set it aside.
Heat the canola oil in a large nonstick or heavy skillet over medium to medium-high heat. When the oil is hot, add the onions and sauté them for about 3 minutes until they are just starting to brown.
Add the garlic and sauté it for about 30 seconds, then stir in the broccoli and about 2 Tbsp. of water.
Cover the pan, reduce the heat, and steam the broccoli for about 8 minutes until it is just fork tender, lifting the lid once or twice to stir it.
Drain the noodles, return them to the pot, add the vegetables and the sauce and stir it all together. Serve it immediately or refrigerate it for up to 3 days.