Whisk up dressing ingredients in large mixing bowl and set aside.
In a saucepot, cover farro with 2 inches water, bring to a boil, season with salt and cook 20 minutes to al dente; drain.
Add farro, cucumber, tomatoes, scallions, red onion, peppers, mint, parsley, walnuts, feta, olives and pepperoncini to a mixing bowl. Add dressing and toss to combine. Season with salt and pepper to taste, and serve.