Cook the Grano by combining 8 cups water, salted as you would for pasta, and Grano in a large pot. Bring to a boil, then reduce heat to medium. Simmer, stirring frequently, until Grano is tender but still chewy, about 30-35 minutes. Drain well and set aside in refrigerator to chill.
Meanwhile, in a medium bowl, whisk together olive oil, vinegar, garlic, Italian seasoning, salt and pepper. In a large bowl, combine remaining ingredients and chilled Grano. Add dressing, toss well and serve.