Rinse 1 cup of farro under cold water. In a medium saucepan, combine the farro with 3 cups of water or vegetable broth and a pinch of salt. Bring to a boil, then reduce heat to maintain a gentle simmer. Cook uncovered for 25-30 minutes until the farro is tender but still has a pleasant chew.
Drain any excess liquid and spread the cooked farro on a baking sheet to cool quickly.
While the farro cooks, prepare your vegetables. Dice the cucumber into ½-inch pieces, halve the cherry tomatoes, finely dice the red onion, and chop the bell pepper into small, uniform pieces.
In a small bowl or jar, combine the olive oil, lemon juice, red wine vinegar, minced garlic, dried oregano, Dijon mustard, sweetener, salt, and pepper. Whisk vigorously or shake in a sealed jar until the dressing is well emulsified.
In a large bowl, combine the cooled farro with the prepared vegetables, olives, and herbs.
Pour about three-quarters of the dressing over the ingredients and toss gently to combine.
Add the crumbled feta cheese and fold in carefully to maintain its texture. Taste and add additional dressing if needed.
For best flavor, allow the salad to rest for at least 30 minutes before serving to let the flavors meld properly.