Combine 2 tablespoons vegetable oil, the soy sauce, lemon juice, onion, brown sugar, garlic, sesame oil, and pepper to taste in a bowl or large resealable plastic bag. Add the salmon and turn to coat; refrigerate for at least 3 hours, preferably most of the day.

Preheat the broiler and line a broiler pan with foil. Place the salmon on the foil (reserve the marinade) and brush with vegetable oil. Broil for 5 to 7 minutes, or until the salmon is opaque. Meanwhile, strain the marinade and simmer in a saucepan over medium-low heat until slightly reduced. Serve the salmon with the sauce on the side.

Photograph by Ngoc Minh Ngo