In a medium bowl, whisk the sauce ingredients until combined. Chill until ready to use.
PREPARE THE SALMON:
Preheat the grill and spray the hot grill rack with nonstick cooking spray. Grill the salmon over hot coals for 2 minutes per side, turning to make diamond or square grill marks for presentation. Remove the salmon to a platter and cover to keep warm.
PREPARE THE SPINACH:
Heat the wine in a large sauté pan over medium-low heat. Sauté the garlic in hot wine for 1 minute. Add the spinach to the garlic mixture and sauté just until the spinach turns bright green and wilts. (If the garlic sticks to the pan, add 1 to 2 tablespoons vegetable broth or water). Sprinkle the spinach with nutmeg and pepper.
TO SERVE:
Pat the spinach dry and portion evenly on 4 plates. Arrange the salmon so as to partially cover the spinach and drizzle with the sauce. Garnish each plate with 1 sprig of dill weed and 1 lemon wedge.
Notes
If you wish to use frozen spinach instead of fresh, you'll use a 10-ounce package of frozen spinach (thawed and squeezed dry).