Pluck off the ends of the green beans and cut them into one-inch lengths.
Drop them into boiling water to cover and let simmer eight or 10 minutes, depending on size, until crisp-tender.
Drain immediately.
Peel and devein the shrimp and set aside.
Bring the water to a boil for the ziti.
Do not add the ziti.
Crush the tomatoes or blend them in a food processor.
Heat two tablespoons of the oil in a saucepan and add one-half teaspoon of minced garlic.
Cook briefly and add the tomatoes and tomato paste.
Add salt and pepper.
Cook down, stirring, about 20 minutes or until reduced to about two and one-half cups.
Meanwhile, drop the ziti into the boiling water and cook about 14 minutes.
As the ziti cooks, heat the remaining two tablespoons of oil in a large, heavy skillet and add the shrimp, chili pepper and remaining tablespoon minced garlic and cook, stirring, about one minute.