Place the pork in the freezer about 10 minutes to make it easier to slice. Soak the noodles in very hot water until just tender, about 10 minutes; drain. Snip the noodles with scissors into shorter lengths. Cut the frozen pork crosswise into 1/4-inch-wide strips.
Puree the cilantro, lime zest and juice, ginger, garlic, jalapenos, shallots, fish sauce, brown sugar and 1 tablespoon water in a food processor until smooth, scraping down the processor as needed.
Heat 3 tablespoons peanut oil in a large skillet over high heat. Add half the cilantro mixture and stir-fry 1 minute. Add the pork and stir-fry until no longer pink, 2 to 3 minutes. Transfer the pork with a slotted spoon to a plate. Add the remaining 1 tablespoon peanut oil to the skillet; add the green beans and stir-fry until tender, 4 to 5 minutes. Add the noodles, pork and 2 tablespoons of the remaining cilantro mixture. Cook, tossing with tongs, until heated through, about 2 minutes. Stir in the remaining cilantro mixture to taste.
Photograph by Antonis Achilleon