Bring a large pot of salted water to a rolling boil. Add the orzo and cook according to package directions for about 8 to 10 minutes until al dente. Drain and rinse under cold water to cool.

In a mixing bowl, combine diced red bell peppers, orange bell peppers, red onion, cucumber, corn, halved tomatoes, fresh basil, and chopped green onions. Toss gently.

In a small bowl, whisk together olive oil, lemon juice, lemon zest, Dijon mustard, minced garlic, and a pinch of salt and pepper until smooth.

Add the cooled orzo to the bowl of vegetables. Pour the dressing over and toss everything together thoroughly.

Serve immediately or refrigerate for up to four days. Add fresh basil before serving to maintain flavor.