Arrange the fish in a single layer in a microwave-safe baking dish. Set aside.

Place the water, vinegar, onion, bay leaf, salt, and pepper in a two-quart measuring cup. Partially cover with plastic wrap. Microcook on high for for to five minutes, until the liquid reaches a high simmer/low boil.

Carefully pour the hot poaching liquid over the fish fillets, just to cover, leaving the solids in the cup. You may not use all of the liquid. Partially cover the salmon tightly with plastic wrap and carefully place in the oven. Microcook on medium, (50 percent power) for five minutes (three and a half to four minutes per pound), until slightly underdone. Remove from the oven and let stand in the liquid for two minutes.

Place all of the sauce ingredients in the two-cup measuring cup. Beat with a fork to combine and loosen the mayonnaise. Microcook on low (10 percent power) or defrost for one to one and a half minutes, until runny and warm. Stir.

Remove the fish with a slotted spatula to individual dinner plates and coat lightly with four to five tablespoons of the lemon sauce. Serve immediately.