In a small bowl, whisk together the tamari, mirin, sugar, and garlic until the sugar dissolves.
Place the salmon filets in a shallow container. Pour the marinade over the fish, turning to coat evenly.
Cover and transfer to the refrigerator to marinate overnight.
Preheat the oven to 400°F.
Remove the salmon from the marinade and place on a lined baking sheet.
Transfer to the oven and bake for 11 minutes.
Turn on the broiler and broil for 1–2 minutes until the top of the fish turns golden. Remove from the oven.
Add your cooked white rice to a bowl.
Top with the salmon and garnish with cilantro microgreens.