In a deep skillet or soup pot, heat 2 tablespoons EVOO, two turns of the pan, over medium-high heat. Add the orzo and toast for 2 minutes. Add the zucchini, tomatoes and green beans; season with salt and pepper. Cook until the tomatoes are softened, 8-10 minutes. Add the wine and boil for 1 minute. Add the chicken stock and bring to a boil, then lower the heat and simmer for 5 minutes. Stir in the scallions and cook until the orzo is al dente, about 3 minutes.
While the soup is working, in a food processor, puree the basil, cheese, parsley, tarragon, pine nuts, garlic, lemon peel and lemon juice. Scrape down the sides and then, with the processor on, pour in the remaining 1/3 cup EVOO. Season with salt and pepper and transfer to a small bowl.
Divide the soup among four bowls and stir in some pesto. Serve with the bread.