Cook the Farro: Cook the farro according to package instructions. Once tender, drain any excess water and spread the grains on a baking sheet to cool completely. This ensures the greens remain crisp upon assembly.
Toast the Walnuts: While the farro cools, place the chopped walnuts in a small, dry skillet over medium heat. Toast for 3-5 minutes, shaking the pan frequently, until fragrant and lightly browned. Immediately remove from the skillet and set aside to cool.
Prepare the Vinaigrette: In a small jar with a tight-fitting lid or a small bowl, combine all vinaigrette ingredients: extra virgin olive oil, lemon juice, apple cider vinegar, minced garlic, and Dijon mustard. Season generously with black pepper. Shake or whisk vigorously until the dressing is emulsified and creamy.
Combine Salad Ingredients: In your extra-large mixing bowl, combine the cooled farro, thinly sliced apple, shaved fennel, radicchio, arugula, sliced dates, parsley, and thyme leaves.
Dress the Salad: Pour about two-thirds of the prepared vinaigrette over the salad. Using gentle tongs, toss everything together until every component is lightly coated.
Finish and Serve: Gently fold in the toasted walnuts and the crumbled goat cheese, being careful not to break up the cheese too much. Taste and add the remaining dressing if desired. Serve immediately.