Make the Crispy Shallots: Scatter the shallots evenly over the surface of an 8x8-inch glass dish. Pour the oil over the shallots and microwave on high until the shallots are browned and crisp, 6–8 minutes. (Begin checking them at 6 minutes, as they can darken quickly). Remove, strain through a fine strainer, drain the shallots on a paper towel, and season with salt. Reserve the shallot oil for another use.
Make the Rice Noodle Salad: Place the noodles in a large bowl, cover with boiling water, and soak for 4 minutes. Drain very well, pat dry with paper towels, return to the bowl (make sure you dried them out) then toss with 2 tablespoons of the sesame oil.
Combine the remaining tablespoon sesame oil in another bowl with the rice vinegar, sambal oelek, lime juice, and fish sauce. Toss the noodles with half the dressing, then toss with most of the cilantro, scallions, mint, basil, and jalapeño, if using. Toss with the rest of the dressing, then top with the remaining herbs, crispy shallots, and peanuts. Toss and serve immediately.