Whisk the soy sauce, olive oil, sesame oil, fish sauce, sugar, lime juice, mirin, ginger, and chile if using in a small bowl until well combined. Set aside.
Bring a large pot of water to a boil. Fill a medium bowl with ice water and set aside. Add the green beans to the boiling water and cook until slightly tender but still very crisp, 1 1/2 to 2 minutes. Using a slotted spoon, remove the green beans from the pot and immediately plunge into the ice water. Drain and set aside. Add the rice noodles to the boiling water and cook according to the package instructions. Drain and rinse the noodles under cold water. Transfer the noodles to a large bowl, add the cooked green beans, and toss with three-quarters of the dressing. Set aside and reserve the remaining dressing.
Heat a 10-inch cast-iron skillet over high heat until very hot. Add the canola oil, swirling the pan to evenly coat the bottom. Dry the steak well with paper towels and sprinkle generously on both sides with salt and pepper. Add the steak to the skillet and cook without moving for 5 minutes. Flip and cook to the desired doneness, about another 4 minutes for medium rare (depending on the thickness of the steak). Allow the steak to rest for 5 to 10 minutes before cutting into thin slices.
Transfer the noodles and green beans to a large platter and arrange the steak over the top. Drizzle with the remaining dressing and any accumulated juices from the steak. Sprinkle with the cilantro and peanuts to garnish.
This noodle salad is also a great way to utilize any leftover steak you may have. Depending on your tolerance for heat, you may want to add only a portion of the minced red chile, or omit it altogether. While any rice noodles would work for this salad, I prefer to use the 3-millimeter-wide flat variety.