Pat salmon dry and season with salt and pepper. Heat oil in a 12-inch nonstick skillet over moderately high heat until hot but not smoking, then sauté salmon in 2 batches, starting with skinned sides up and turning over once, until just cooked through, 6 to 9 minutes per batch. Transfer to a platter and keep warm, covered.
Remove skillet from heat and cool 1 minute. Whisk in remaining ingredients and salt and pepper to taste. Pour sauce over salmon.