Cook the orzo according to package directions for al dente consistency. Drain in a colander and rinse with cold water. Transfer to a large bowl and set aside.

In a small bowl, combine the olive oil, lemon juice, Dijon mustard, salt, and ground black pepper. Pour the mixture over the cooked orzo and toss to coat.

Stir in the tomatoes, red onion, scallions, basil, and mint. Add the feta cheese and toss gently to distribute throughout.

Adjust seasoning to taste and serve immediately or refrigerate for later.