1. Put potatoes into a medium saucepan; cover with cold water, and bring to a boil. Reduce heat, and simmer until just tender, about 6 minutes. Drain; set aside.

2. Meanwhile, melt butter in a large nonstick skillet over medium heat. Add onion; cook, stirring occasionally, until softened, about 6 minutes. Add wine; cook until liquid has almost evaporated. Add potatoes, cream, and 1/2 cup water. Simmer until sauce is creamy, about 12 minutes. Add peas; cook 2 minutes.

3. Arrange salmon over lettuce on plates. Spoon potato mixture over top; sprinkle with dill, and season with salt and pepper. Serve immediately.