Sprinkle the salmon with salt. Put the wine, water, fennel and onions in a sauté pan and bring to a simmer.

Add the salmon fillets, skin-side down in the pan. Cover and cook 5-10 minutes, (carefully turn the pieces over half way through cooking time) depending on how thick the salmon is to your desired doneness.  Do not overcook and you do not want your water to get hot enough to boil -- just barely simmering.

To serve, plate the salmon and then top with a ladle of the Lemon Caper Yogurt Sauce and serve any extra sauce on the side.

For the sauce: In a small bowl, mix together the yogurt, capers, lemon juice, and lemon zest. Season with salt and pepper, to taste.