Cook the orzo in a large pot of salted boiling water according to package instructions, usually around 7-9 minutes until al dente. Drain and set aside to cool.

In a large mixing bowl, combine the diced red bell pepper, diced orange bell pepper, chopped red onion, diced cucumber, corn, halved cherry tomatoes, chopped basil, and sliced green onions. Toss together.

Add the cooled orzo to the vegetable mixture and gently toss to combine.

In a small bowl, whisk together olive oil, lemon juice and zest, Dijon mustard, minced garlic, salt, and pepper to make the dressing.

Pour the dressing over the salad and toss gently to coat all ingredients.

Transfer the salad to a serving dish or individual bowls, garnish with grated Parmesan cheese and serve immediately or refrigerate for at least 30 minutes before serving.