Make vinaigrette: Whisk together honey, mustard, vinegar, sour cream, and 1/2 teaspoon salt. Whisking constantly, add oil in a slow, steady stream; whisk until emulsified. Set vinaigrette aside.
Using a vegetable peeler, shave cucumber lengthwise on four sides to yield 20 thin ribbons; discard core. Halve ribbons crosswise.
Using a fork, flake salmon fillet into 1- to 1 1/2-inch pieces. Toss frisee, dill, and cucumber ribbons in a bowl. Season with salt and pepper. Divide frisee mixture among plates, and top each with some of the salmon. Drizzle vinaigrette over each.