- Prepare the Oven: Adjust an oven rack to sit about 6 inches from the top heating element. Turn the broiler on HIGH to preheat for at least 5 minutes. 
- Mix the Glaze: In a small bowl, whisk together the low-sodium miso, rice vinegar, coconut aminos, maple syrup, toasted sesame oil, minced garlic, grated ginger, and water until completely smooth. 
- Glaze the Salmon: Pat the salmon fillets completely dry with a paper towel and place them in a 10-inch oven-safe skillet. Spoon about two-thirds of the glaze over the tops of the fillets, spreading it evenly. 
- Broil: Place the skillet under the hot broiler for 4 to 6 minutes. The initial cook time will cook the salmon most of the way through. 
- Finish with Final Glaze: Carefully remove the skillet from the oven. Brush the remaining glaze over the salmon. Return it to the broiler for another 1 to 2 minutes, just until the glaze is bubbling and the fish is cooked through. The salmon is done when it flakes easily with a fork. 
- Garnish and Serve: Let the salmon rest for a minute. Garnish with toasted sesame seeds and sliced green onions before serving immediately.