In a large Dutch oven or sturdy pot, warm about 2 tablespoons of extra virgin olive oil until it shimmers. Incorporate the chopped onion, celery, carrots, and minced garlic, seasoning generously with kosher salt and freshly ground black pepper. Sauté, stirring from time to time, until the vegetables are tender, about 5 minutes. Pour in the chicken stock and water, then nestle in the chicken breasts. Season again with salt and pepper, sprinkle in the dried oregano, turmeric, and red pepper flakes or Aleppo pepper. Bring everything to a rolling boil, then reduce the heat to medium-low and allow to cook for 10–15 minutes until the chicken is nearly cooked through, skimming any foam that surfaces. Remove the chicken breasts to a plate and add the orzo pasta and frozen peas to the pot, increasing the heat to return the broth to a boil. Meanwhile, shred the chicken using two forks, then stir it back into the pot and continue cooking until the orzo reaches an al dente texture, about 8 minutes more. Remove the pot from the heat and finish the soup by stirring in the fresh lemon juice and zest, chopped green onions, and parsley. Serve immediately.