Prepare grains: Cook wild rice and quinoa separately according to package instructions, adding 1/2 tsp. salt to each. Drain grains of any liquid, then pour out each onto separate rimmed baking sheets and let cool.
Heat oil in a small saucepan over medium-high heat until it reaches 350° on a deep-frying thermometer. Using a slotted spoon, add one-quarter of quinoa; cook until crisp (spoon out a few grains and taste them to test), about 2 minutes. Transfer quinoa to paper towels to drain and repeat to cook remaining quinoa.
Make salad: Preheat broiler with rack about 3 in. from heat. Set salmon on a rimmed baking sheet. Rub all over with oil, salt, and pepper. Broil until medium-rare (cut to test), turning once, 3 to 5 minutes total. Set aside 5 to 10 minutes (salmon will continue to cook a little).
On a large platter, layer wild rice, half of quinoa, the watercress, radishes, onion, parsley, basil, cilantro, and dill. Gently toss greens and vegetables to loosely mix. Break salmon into 4-in. pieces, discarding any skin, and add to platter. Sprinkle with remaining quinoa, taking care not to cover salmon. Spoon about 2/3 cup salsa verde over salad and serve the rest on the side.
*Find black quinoa at well-stocked grocery stores, natural-foods stores, and alterecofoods.com, or use another color of quinoa.
Make ahead: Up to 1 day, prep and chill herbs. Cook grains (step 1) and chill; bring to room temperature to continue.