Preheat grill to medium-high (about 450°F). Process parsley, cilantro, basil, and garlic in a food processor until finely chopped. Add lemon rind, juice, crushed red pepper, 3 tablespoons oil, and 1/4 teaspoon salt; process until finely chopped and well combined. Toss together shrimp and 1/4 cup herb mixture. Thread 4 shrimp onto each of 6 (8-inch) skewers; thread 8 peppers onto each of 2 (8-inch) skewers. Drizzle skewers with remaining 1 tablespoon oil; sprinkle with black pepper and remaining 1/2 teaspoon salt. Place skewers on grill grates coated with cooking spray; grill just until shrimp are done and peppers are charred, 2 to 3 minutes per side. Brush skewers with remaining herb mixture before serving.