Combine all ingredients except tomatoes in a food processor and blend until smooth, scraping sides as necessary. If it's too rustic, add 1-2 tbsp water. Stir in tomatoes and serve.
For a truly fat-free knock off, try using 2 cups of frozen peas (thawed). Also, a little avocado can go a long way. If desired, add 2-4 tbsp avocado for a more authentic taste but still with a lot less fat!