Add salt and pepper to salmon fillets.
In a large, non-stick skillet, over medium high heat, melt 2 tsp of the margarine.
Add salmon to pan and cook for 2 to 3 minutes on each side or until lightly brown.
Move salmon to an oven-proof dish and roast for 5 to 7 minutes.
Wipe skillet with paper towel and add orange juice, balsamic vinegar and onion.
Boil for 2 minutes or until sauce has slightly thickened.
Remove from heat and stir in remaining margarine.
Add in parsley, basil, and mint and stir. Spoon sauce over salmon and serve.