Preheat the oven to 425ºF. Line a baking sheet with parchment paper. Place the salmon on top and season with salt, pepper, and garlic powder. Drizzle with 1 tablespoon orange juice and 1/2 tablespoon orange zest (reserve the remaining for the dressing). Bake for about 20 minutes or until the fish is opaque and flakes easily with a fork.
In the meantime, make the vinaigrette. In a small bowl add the shallot, 1/4 cup of orange juice and 1 tablespoon orange zest, mustard, white wine vinegar, parsley, and cilantro. While whisking, slowly stream in the olive oil. Season with salt and pepper to taste. Set aside.
With the remaining two oranges, zest both oranges and the segment them, reserving all juice. Cut the top and bottom off of the navel orange. Then using a smaller knife, carefully cut the skin from top to bottom off of the orange. Using a paring knife, remove each orange segment from the pith into the bowl. There will be extra juice from the orange that will collect in the bowl, reserve this and set it aside for later.
When the salmon has finished cooking, remove from the oven. Let cool for 10 minutes. Break the salmon into large pieces and place on a platter. Evenly scatter over the salmon the orange segments from the 2 oranges, cucumber, onion, edamame, sugar snap peas, and avocado. Drizzle with as much of the vinaigrette as you desire.
Place the mixed greens on the sides of the broken up salmon. Garnish with more parsley, cilantro, and season with salt and pepper. Drizzle over the reserved orange juice that collected at the bottom of the bowl when you segmented the orange slices. Serve the remaining dressing on the side.