Medium-hot for charcoal or wood; if using gas, set grill for moderate heat and cover grill.
6 (6-ounce) pieces center-cut wild salmon fillet (about 1 inch thick) with skin
Olive oil, salt and pepper
1 whole lime
6 tablespoons lime butter sauce (recipe follows)
1 large clove garlic, chopped
¼ cup fresh lime juice
1 teaspoon salt, to taste or dietary restrictions
½ teaspoon black pepper
1 stick (½ cup) unsalted butter, melted
Finely grate green skin of lime, yielding 1½ teaspoons of zest; reserve for later use.
Cut remainder of lime and extract juice for sauce.
In a blender, covered with center cap removed, purée garlic with lime juice, salt and pepper until smooth.
With motor running, pour in melted butter and blend until emulsified, about 30 seconds.
Mixture may be slightly runny. Pour into container, cover and reserve in refrigerator.
May be made a few days in advance. Season salmon with salt and pepper. Lightly oil grill, or spray or brush olive oil on flesh side of salmon.
Place flesh side down on grill grate; cook 4 minutes.
If using gas grill, set fish over low flame, light additional flame farthest away on medium flame and cover grill; cook 4 minutes.
Turn fillets over and grill (covered only if using gas grill) until just cooked through, 3 to 6 minutes more. Gas grill will cook faster; covering the grill creates an oven, with more concentrated heat.
Sprinkle fillets with zest and top each with 1 tablespoon lime-butter sauce.