Combine the vinaigrette ingredients in a small bowl; stir with a whisk.
PREPARE THE FISH:
Heat a nonstick grill pan over medium-high heat. Coat the pan with cooking spray. Sprinkle the fish with ½ teaspoon salt. Add the fish to the pan; grill 4 minutes on each side or until the fish flakes easily when tested with a fork or until desired degree of doneness. Alternately, you can grill the fish on an "actual" grill!
To serve, spoon the vinaigrette over the fish and sprinkle with chives.