Arrange two oven racks: one in the center and the other ~6 inches from the broiler. Preheat oven to 400ºF.
Prepare rice: Empty chilled rice out onto a large rimmed baking sheet coated with parchment paper for easy cleanup. Add tamari and toasted sesame oil, and toss thoroughly to coat grains. (Note: if you're using lower-sodium tamari or soy sauce, add a good pinch of salt to the rice.) Spread rice in a thin layer and roast on the center rack for 25 to 30 minutes, tossing once halfway through, until crispy. Set aside to slightly cool.
Meanwhile, blend dressing: In a liquid measuring cup or wide-mouth jar, combine all dressing ingredients, and use an immersion blender to blend until smooth. (Alternatively, use a countertop blender.)
Prepare salmon: Place salmon in a baking dish (or on a small baking sheet) coated with parchment paper. Season evenly with 1/2 tsp. kosher salt and 1/4 tsp. black pepper. Drizzle 2 Tablespoons of the Miso-Ginger Dressing overtop and brush to coat.
Broil salmon: Once the rice is done cooking, set the broiler heat to HIGH. Place salmon on the top oven rack (~6 inches from broiler source) and broil until the salmon is opaque with a deep brown crust, about 6 to 8 minutes, rotating the pan once halfway through. Set aside to slightly cool before flaking into large pieces. Discard skin.
Assemble salad: To a large mixing bowl, combine Napa and red cabbage, cucumbers, and cilantro. Season veggies with good pinch of kosher salt. Add crispy rice, flaked salmon, sesame seeds, and remaining Miso-Ginger Dressing; toss well to combine. Garnish with extra fresh herbs and toasted sesame seeds, if desired. Serve at room temperature.