Bring a large pot of water to a boil. Add the spaghetti and cook it according to package directions, but pull it 1-2 minutes before so it is al dente. Do not salt the pasta water - the seasonings will do the work. If we add salt to the pasta water, it will result in an overly salty finished dish. Reserve a ½ cup of pasta water.
While the pasta is cooking, pat the salmon filets dry and season them with a ½ teaspoon of lemon pepper.
In a pan over medium-low heat, add a little oil and sear the salmon, skin side down. Sear for a few minutes until golden brown and crispy. Flip the salmon and peel the salmon skin off. Enjoy the skin as a snack or discard. If using skinless salmon, sear on both sides until golden.
To the pan, add butter, Old Bay seasoning, sugar, lemon pepper, paprika, onion powder, and oregano. Use a spatula to break down the salmon into chunky pieces and sauté everything together until well combined.
Add in the minced garlic and cook until slightly softened and fragrant. Stir in the fish sauce and sriracha, if using.
Add the cooked spaghetti to the pan along with ¼ cup of pasta water. Toss everything together and gently simmer on low until the sauce begins to thicken and clings to the noodles. Add more pasta water as needed, for a looser consistency. Garnish with scallions and enjoy hot.