Bring a large pot of salted water to a boil and cook orzo according to package directions. In the last 2 minutes of cooking time, add the peas to the pot with the orzo. Drain peas and pasta in large colander, and set aside to cool.
In a small bowl or measuring cup, combine dressing ingredients and whisk to combine.
In a large serving bowl, mix together orzo, peas, cucumbers, carrots, tomatoes, and dressing until everything is coated with dressing. Check for seasoning, add more salt and pepper as needed. Serve immediately or store covered in the refrigerator for up to 2 days.
Pasta will soak up some of the dressing (as shown in these photos – they were taken the day after making the salad). If necessary, add more dressing to achieve desired consistency.