Step 1

Position racks in upper and lower thirds of oven; preheat to 450 degrees F. Line 2 rimmed baking sheets with foil and coat with cooking spray.

Step 2

Bring water and farro to a boil in a saucepan. Reduce heat to low, cover and simmer until just tender, about 30 minutes. Drain if necessary.

Step 3

Meanwhile, toss eggplant, bell pepper, squash, onion and tomatoes with oil, 1/2 teaspoon salt and 1/4 teaspoon pepper in a large bowl. Divide between the prepared baking sheets. Roast on the upper and lower racks, stirring once halfway, until the vegetables are tender and starting to brown, about 25 minutes. Return them to the bowl. Stir in capers, vinegar and honey.

Step 4

Season salmon with lemon zest, Italian seasoning and the remaining 1/4 teaspoon each salt and pepper and place on one of the baking sheets. Roast on the lower rack until just cooked through, 6 to 12 minutes, depending on thickness. Serve the salmon with the farro, vegetable caponata and lemon wedges.