How to Make It
Heat a medium saucepan over medium-high. Add millet and garlic to dry pan; cook, stirring occasionally, until millet is lightly toasted, about 5 minutes. Add 1 1/2 cups water; bring to a boil. Cover, reduce heat to medium-low, and simmer 10 minutes. Add cauliflower; cover and simmer until cauliflower is tender and liquid is absorbed, about 15 minutes. Set aside.
Meanwhile, heat a small skillet over medium. Add 1 tablespoon oil; swirl to coat. Add shallots; cook, stirring often, until softened, about 2 minutes. Stir in vinegar, raisins, sugar, and capers. Reduce heat to medium-low; cook, stirring occasionally, until slightly syrupy, 8 to 10 minutes. Remove from heat; stir in pine nuts.
Transfer millet mixture to a food processor. Add 1 tablespoon oil, 1/2 teaspoon salt, and 1/4 teaspoon pepper; process until smooth, about 20 seconds. (If mixture is too thick, add water, 1 tablespoon at a time, and process until desired consistency is reached.)
Heat a large grill pan over high. Brush flesh side of fish evenly with remaining 1 tablespoon oil; sprinkle evenly with remaining 1/8 teaspoon salt and remaining 1/4 teaspoon pepper. Coat pan with cooking spray. Add fish to pan, skin side down; cook until crisp, about 3 minutes. Turn fish over; cook until flesh flakes easily when tested with a fork, about 3 minutes. Spread about 1/2 cup millet puree on each of 4 plates. Top each serving with 1 fillet, skin side up, and about 2 tablespoons relish. Sprinkle servings evenly with parsley and dill.