1. Cook farro according to package instructions. Let cool or store in the fridge.
2. For the dressing, combine all ingredients besides the oil in a blender. Blend for 20 seconds, then slowly drizzle in the oil to emulsify. Store in an airtight container in the fridge. This recipe is for one quart and will keep in the fridge for around two weeks or more.
3. In a bowl, combine lettuce, arugula, onion, raisins, farro. Toss with dressing and transfer to a serving bowl. Sprinkle with goat cheese.