salmon filets, skin removed
Heat a medium-sized nonstick skillet and spray with vegetable oil spray.
Brown salmon for 3 minutes on high, turn and brown another 3 minutes.
Transfer salmon to plate; add vinegar to skillet and cook on high heat until about half the amount remains, about 3 minutes.
Add mustard and mix well to make a smooth glaze.
Salt and pepper salmon, return to skillet and cook 1 minute.
Turn to coat both sides with the glaze and cook another minute or two, until cooked through.
Divide salmon into two portions and place on plates.
Spoon any remaining glaze on top.