Cook orzo in a large pot of boiling water according to package directions then drain and pour into a large bowl.
Add the lemon juice and olive oil to hot pasta and season with salt and pepper.
Toss shrimp with the olive oil, lemon zest and remaining herbs and spices for the grilled shrimp.
Preheat grill or grill pan to medium high heat and place shrimp on the grill. Grill on each side for about two minutes or until no longer pink. Remove and set aside when done.
Add the shrimp to the orzo and then add the herbs, cucumber, red onion, scallions and toss well. Gently fold in the feta.
Season with salt and pepper to taste. Serve immediately or refrigerate overnight but add tomatoes before serving to keep them fresh.