Bring a large pot of water with 1 tsp of salt to a boil. Cook the orzo according to the package directions. I recommend letting it cool by adding it to a large bowl and placing it in the fridge. While rinsing it in cold water is quicker, it may diminish some salt and flavor.
Make the dressing by whisking together the olive oil, balsamic vinegar, Dijon mustard, water, and Italian seasoning until emulsified. Set aside.
Preheat your grill to high heat or oven to 400°F. If you are grilling and using wooden skewers, start soaking them in water now.
Begin by patting your peeled and deveined shrimp dry using paper towels. Marinate the shrimp with half of the prepared dressing in a ziplock bag or bowl, adding the minced garlic. Reserve the remaining dressing for the orzo. Place the shrimp in the refrigerator to marinate for about 20 minutes but no more than 1 hour.
While the oven or grill is preheating, prepare the vegetables by chopping the pepper, cucumber, and parsley.
Make the Salad: Once the orzo has cooled, mix it with the prepared vegetables, including the arugula. The arugula will wilt slightly as you toss the salad. If the orzo sticks together, add a splash of water or the reserved dressing to help separate it as you toss. Drizzle with the reserved dressing and toss again.
Baking Shrimp: Place the shrimp on a non-stick baking sheet and bake for 5-7 minutes until they turn pink and are cooked through (avoid overcooking).
Grilling Shrimp: Thread 5 - 6 shrimp onto each skewer. Grill the shrimp skewers for 2-3 minutes on each side until they are cooked through.
Add the cooked shrimp to the cold salad and serve immediately. Drizzle with more dressing if desired, and sprinkle with parsley for garnish.