In a large pot, heat the oil over medium heat. Add the garlic, onion and crushed red pepper and cook over medium heat until the onion is translucent, about 7 minutes. Add the chicken broth and the tomatoes and their juice, bring to a boil, then lower the heat and simmer for 10 minutes.
Add the cumin, salt, lime juice and tortillas and simmer for 2 minutes.
In a blender, puree the soup in batches. Garnish with cilantro and serve.