Bring a large pot of water to a boil. Add the farro and 1 teaspoon of salt. Cook for 15-20 minutes until tender but still chewy. Drain and set aside to cool.
Whisk together the remaining teaspoon of salt, black pepper, sugar, olive oil, and red wine vinegar. Set aside.
Slice the grapes in half.
Cut the celery into thin half-moon slices.
In a large bowl, combine the cooked farro, grapes, celery, kale, and parsley. Pour the dressing over the salad and toss to coat evenly.
Sprinkle the toasted walnuts on top just before serving for extra crunch.