Basic Grilled Fish with Vegetable Vinaigrette

steps

1. Prepare a charcoal grill for two-zone cooking and build a medium fire, or heat a gas grill to medium-high. Carefully wipe preheated grates with a lightly oiled paper towel. Using a grill brush, scrape grill grates clean, then carefully wipe with lightly oiled towel again.
2. Halve fennel bulb lengthwise and cut each half into 1-inch wedges, keeping the root intact to help the wedges hold together on the grill. Cut onion into ½-inch rounds. Quarter radicchio, keeping the stem intact.
3. Grill fennel, onion, and radicchio over direct heat, turning as needed for even cooking, until the fennel and onion are lightly charred and cooked through but still have a little bite, about 20 minutes. The radicchio is ready when the leaves are wilted and the tips crackly, about 15 to 20 minutes.
4. As they finish, place grilled vegetables in a bowl and cover with plastic wrap. Once fully cool, chop vegetables into roughly ½-inch pieces. Return vegetables to bowl and combine with oil, vinegar, salt, garlic, capers, and chiles. Stir in mint and marjoram.
5. On a baking sheet or large plate, brush or drizzle each steak with 2 teaspoons olive oil and season generously with kosher salt on both sides. Carefully place fish on grill over direct heat. Cook 3 to 4 minutes per side for medium rare, 120 to 125 degrees.
6. Transfer fish to a serving dish. Top with vinaigrette, lightly drizzle with olive oil, sprinkle with pepper and flaky salt, and serve with lemon wedges.