Place the farro in a large bowl and cover with cold water. Soak for 30 minutes.
Then put the farro in a large pot and cover with the chicken stock and 4 cups cold water. Set over high heat and bring to a boil. Turn down the heat to a simmer and cook uncovered until the farro is tender, 25 to 30 minutes. Drain the farro and toss with the olive oil and red wine vinegar. Season with some salt and pepper. Allow to cool slightly.
In a large bowl, toss the farro together with the arugula, tomatoes, apples, cucumber and orange supremes. Refrigerate until ready to serve.