For the soup:
Heat the olive oil in a medium saucepan. Sauté the onions about 3 minutes. Add the garlic and cook and stir until the onions are soft and translucent, a few more minutes. Stir in the tomatoes and cook about 5 minutes, stirring frequently. Then add the broth and the corn, if using. Simmer 15 to 20 minutes. Chop the chipotles and add them. Season to taste with sea salt.
For the garnishes:
In a large skillet heat the peanut oil over medium heat. Fry the tortilla strips until they are just beginning to get crisp. Drain on paper towels. Put the tortilla strips, the cheese, avocado, cilantro and chicken in separate bowls.
To serve:
Put some cheese and tortilla strips, a couple of avocado slices and the cilantro in each person's bowl. Add the chicken, if desired. Ladle the hot tomato broth over the garnishes.