Make the dressing. In a bowl, vigorously whisk together the olive oil, lemon zest, lemon juice, salt and pepper. Refigerate until ready to use. Cook the Orzo: In a saucepot, add the orzo. Cover with water two inches above the orzo. Bring to a boil and simmer until cooked, about 25-30 minutes. Drain, (do not rinse) and set aside to cool. Cook the vegetables: While orzo is cooking, bring a large saucepan of water to a boil over high. Add asparagus and sugar snap peas to boiling water. Cook until bright green and tender-crisp, about 2 minutes. Add English peas, and stir until softened, about 30 seconds. Using a slotted spoon, transfer vegetables to an ice bath, reserving boiling water in saucepan. Cook the shrimp. Add the shrimp to the boiling water. Cook until opaque, about 3 minutes, and then drain. Transfer shrimp to ice bath with vegetables. Let stand until chilled, about 3 minutes and then drain. In a large serving bowl, mix the shrimp and orzo salad together. Add the vegetables and gently toss to combine. Add chives, parsley, and tarragon. Drizzle the dressing over the salad and toss gently to combine. Chill until ready to serve.