For the sauce: Blend sour cream, water, juice, salt, and chives in a blender until mixture just turns pale green. Season with pepper.
For the fish: Preheat oven to 450 degrees F. Remove any pin bones from fish with tweezers or needle-nose pliers and pat fish dry with paper towels. Score skin in several places with a thin sharp knife to prevent fish from curling (do not cut through flesh) and season fish with salt and pepper.
Heat oil in a 12-inch nonstick skillet over high heat until hot but not smoking, then sear fish, skin sides down, in 2 batches until skin is golden brown and crisp, 3 to 4 minutes (fish will not be fully cooked). Transfer, skin sides up, to an oiled shallow baking pan.
Roast fish, uncovered, in middle of oven until just cooked through, 7 to 8 minutes.
Spoon 3 tablespoons sauce onto each of 6 plates and top with Spicy Garlic Potatoes and Zucchini. Squeeze 1 lemon wedge over each fillet, then place fish, skin sides up, over vegetables. Top fish with sprouts.
Cover potatoes with salted cold water by 1 inch in a 4-quart saucepan, then simmer, uncovered, until just tender, about 20 to 25 minutes. Drain in a colander and let stand until cool enough to handle, about 15 minutes. Peel potatoes and halve lengthwise.
Cook garlic in oil in a 12-inch nonstick skillet over moderate heat, stirring, until garlic is pale golden, about 2 minutes. Discard garlic, then stir potatoes and red pepper flakes into oil and saute over moderately high heat, stirring occasionally, until potatoes begin to turn golden brown, 8 to 10 minutes.
While sauteing potatoes, cook zucchini in a pot of boiling salted water until just tender, about 2 to 3 minutes, and then drain in a colander.
Transfer potatoes with a slotted spoon to a bowl, then add zucchini to oil in skillet and saute over moderately high heat, stirring, until hot, about 1 minute. Return potatoes to skillet and stir in salt.
Recipe courtesy of Gourmet Magazine