Begin by bringing a large pot of salted water to a boil. Add orzo pasta and cook for 7-10 minutes until al dente. Drain and rinse under cold water.

Chop vegetables: Dice bell peppers, slice cucumber, and halve cherry tomatoes. Set aside in a large bowl.

In a separate bowl, whisk together olive oil, red wine vinegar, and Dijon mustard. Add salt and pepper to taste. Whisk until emulsified.

Combine cooled orzo with chopped vegetables and crumbled feta. Pour vinaigrette over and toss gently to combine.

Serve immediately or refrigerate for later use. If making ahead, hold back some vinaigrette to add before serving.