Combine all sauce ingredients except the lime juice and cornstarch.
In a separate bowl, mix the cornstarch into the lime juice until no clumps remain.
Whisk the lime/cornstarch mixture into the sauce. Set aside.
Cook noodles according to package directions.
Drain and rinse thoroughly.
If your noodles are not done at the same time as your veggies, rinse with additional water and toss with your fingers (wash those hands!) every couple minutes so they don't stick together.
While the noodles cook, heat the peanut oil in a large skillet.
Add the onion and cook for a few minutes, until softened.
Add the remaining vegetables and cook over medium heat, stirring frequently, until starting to cook down (about 5 minutes).
Pour in the sauce and cook until just slightly thickened, about 3 minutes.
Add the noodles and stir until all ingredients are incorporated and coated with the sauce.
Serve warm with crunchy chow mein noodles, if desired.