Combine the olive oil, soy sauce, sesame oil, ginger, maple syrup, Chinese mustard, Sriracha and garlic in a large bowl. Pour one-third of the mixture into a small bowl and reserve. Add the salmon fillets to the large bowl. Cover and let marinate in the refrigerator for 30 minutes.
Heat a large nonstick skillet over medium-high heat. Add a drizzle of olive oil to coat the skillet. Add the salmon skin-side down and cook until crispy, 5 minutes, lowering the heat if the glaze starts to get too dark in the pan. Baste the flesh side with the reserved marinade. Flip and cook until the salmon is cooked through and the flesh side is golden brown, 3 to 4 more minutes. Transfer to a platter and top with the chopped scallions and sesame seeds.