Rub flank steak with olive oil to coat. Scatter the fennel seed, salt, sliced garlic and rosemary over the meat and rub evenly to distribute. Wrap and refrigerate for several hours or overnight. Bring meat to room temperature before cooking, about 1 hour or so.
Heat cast-iron skillet, grill pan or outdoor grill to medium-high heat. When cooking surface is very hot, add meat and cook about 12 minutes, turning once. Transfer meat to a carving board and let it rest about 10 minutes. Slice the meat against the grain, douse with juice of 1/2 lemon. Top meat with greens, cheese and olives. Dress the greens with juice of remaining half-lemon and drizzle with more olive oil.
Rub charred bread with halved garlic. Dress with oil and salt then rub halved tomatoes into the bread, soaking it with the juice and flesh of the tomato.