Heat 1 cup rice vinegar over medium heat with any spices and aromatics, a few sprigs of dill, a pinch of salt, and a few whole black peppercorns. Place 1 sliced red onion in a heat-safe container and pour the hot vinegar mixture over the onions. Set aside or in the fridge and allow to cool.
Rinse your sushi rice thoroughly until the water runs clear. At least 3 times of rinsing and draining. Add 2 cups of rinsed sushi rice and 2 cups of water to the rice cooker. To the top of the rice, add the roughly sliced ginger, 3-4 garlic cloves, and the scallions cut into thirds. Close the lid and press the ‘Cook’ button.
Approximately 10-15 minutes before the rice cooker is done, open it up and place the salmon filet(s) on top of the rice. Close the lid and resume cooking.
In a separate heat-safe bowl, add 3 tbsp minced ginger and 3 tbsp sliced scallions. Heat up 1/4 cup neutral oil in a pot on the stove to at least 300-350ºF. Carefully pour the hot oil over the scallion and ginger. Allow to sizzle until it stops. Add a generous pinch of kosher salt and MSG. Stir to combine.
Optional Sriracha sauce: Combine 3 tbsp sriracha with the juice of 1 lime. Mix in minced or grated garlic and ginger to your preference. Add a splash of soy sauce.
Once the salmon and rice are done cooking, remove any large pieces or ginger, garlic, or scallion. Serve the salmon on top of hot rice. Add the ginger scallion oil sauce on top of the fish, along with the sriracha sauce. Garnish with pickled red onion and any extra sliced scallions.