In a small baking dish, combine soy sauce, brown sugar, and 3 tablespoons of the rice wine vinegar. Season with kosher salt and black pepper.
Place the salmon skin-side up in the marinade and refrigerate for at least 2 hours, ideally overnight.
Preheat broiler with rack in the top third of the oven.
Transfer salmon skin-side up to a foil-lined baking sheet, discarding the marinade.
Broil the salmon for 5 to 7 minutes, or until cooked through and the skin is bubbling and crisp.
While the salmon cooks, toast the sesame seeds in a dry pan over medium heat until golden and fragrant, about 3 to 4 minutes.
In a medium bowl, toss the shallot rings with the remaining 1 tablespoon of rice vinegar. Let sit for 5 minutes, then add toasted sesame seeds, cilantro, and sesame oil. Toss well and season to taste.
Plate the salmon and top generously with the sesame-herb salad. Serve immediately.