I am unsure if this is like the one that is served in restaurants, but it is one I have used. It is based on the one in the Betty Crocker cookbook~
2 tablespoon olive oil
2 cloves garlic, minced
1 teaspoon minced onion
1/2 teaspoon dried oregano
2 1/2 teaspoons chili powder
1/8 teaspoon ground black pepper
1/8 teaspoon salt
1 teaspoon ground cumin
1 (28 ounce) can tomatoes
1 Heat the oil in a large saucepan over medium heat. Add the garlic and saute until light brown. Add the onion, oregano, chili powder, ground black pepper, salt, cumin, and tomatoes. Break up tomatoes.
2 Mix together and then stir in the water. Bring to a boil, reduce heat to low and simmer for 15 to 20 minutes.