In a medium saucepan, combine 4 cups of water with the farro. Bring to a boil over high heat. Cover and simmer over medium-low heat until the farro is almost tender, about 20-30 minutes. Drain well. Transfer to a large bowl and let cool. (If you have soaked the Farro ahead of time, cooking time will be around 20 minutes. If not, cooking time will be closer to 30 minutes.)
While Farro is cooling, bring a pot of salted water to a boil over high heat. Add the green beans and cook for 2 minutes. Drain the green beans.
Once the farro has cooled add the green beans, olives, red pepper, cheese, spinach and corn. Stir to combine. In a small bowl mix together the vinegar, olive oil, mustard, pepper, and the salt. Stir to combine. Pour the vinaigrette over the farro salad. Toss to combine and serve.