Preheat the oven to 400ºF and line a baking sheet with aluminum foil. Brush the chicken breast with 2 tablespoons olive oil on both sides and generously season with 1/2 teaspoon salt and pepper.
Place the chicken on the baking sheet. Bake for 25 minutes until the chicken breast is completely cooked. Let it cook for a few minutes and then shred or chop it.
As the chicken is cooking in the oven, heat the remaining olive oil in a large pot. Saute onion and garlic in olive oil over medium heat until golden brown.
Add in carrots and saute for a couple of minutes. Add the potatoes, dried oregano, paprika, cumin and the remaining salt to the soup and stir well.
Pour in the chicken stock and bring the soup to simmer. Add the orzo to the soup and let the soup cooks on medium until the orzo is completely cooked. Add the shredded chicken back to the soup.
Stir in spinach, dill and lemon juice. Let the soup cook for a few minutes until the spinach is wilted. Taste the soup and add more salt or lemon if you like. Serve warm.