For the Vinaigrette: Whisk together ingredients for the vinaigrette in a small bowl, seasoning generously with salt and pepper. Reserve.
Step 2
For the Salad: Place farro and water in a medium saucepan with onion, garlic, carrot, and 2 teaspoons salt and bring to a boil over medium-high heat. Reduce heat to medium-low, partially cover, and simmer until farro is just tender, about 20 minutes. Drain, discard onion, garlic, and carrot and transfer to a bowl to cool.
Step 3
Gently fold remaining salad ingredients into cooled farro. Add vinaigrette, starting with a few tablespoons at a time. Taste, season with salt and pepper, and add additional vinaigrette as needed. Serve immediately.