Bring a pot of salted water to a boil and cook the orzo according to the package instructions. Drain and rinse the orzo under cold water.
In a large bowl, combine the cooked orzo, cherry tomatoes, bell peppers, red onion, parsley, and feta cheese (if using).
Whisk together the olive oil, red wine vinegar, basil, mustard, and oregano in a small bowl—season with salt and pepper to taste.
Pour the dressing over the orzo mixture and toss to combine.
Serve the orzo salad chilled or at room temperature. Enjoy!