Cook the noodles according to the package directions.
In a small bowl, mix the soy sauce, sherry, cornstarch, brown sugar, ginger, chili paste, garlic and the juice of half the lime. Pour a third of the marinade into a bowl with the sliced beef and toss to coat. Reserve the rest of the marinade for later.
Heat 1 tablespoon of the oil in a large skillet over medium-high to high heat. When it is very hot, throw in the onions and cook for a minute or so. Add the bell peppers and jalapenos. Cook for a minute, tossing until the peppers have brown/black bits but are still firm. Remove the vegetables to a plate.
Into the hot skillet, add the remaining tablespoon of oil. Add the meat mixture, evenly distributing it over the surface of the skillet. Allow to sit for 45 seconds, then turn with tongs. Cook for another 30 seconds, then add the onions and peppers back into the skillet. Reduce the heat to low. Pour in the remaining marinade and stir. Allow to simmer on low for a few minutes; the sauce will slowly thicken. Turn off the heat.
Drain the noodles, then add half of them to the stir-fry. Toss and add more noodles as desired. Stir in some very hot water if needed to thin the sauce.
Top with basil and cilantro leaves and serve immediately with a squeeze of the remaining lime half.