Heat oil in a large soup pot over medium-high heat. Add onion and salt and sauté until onions start to sweat, about 4 minutes.
Add garlic, celery, carrot and zucchini to the pot and continue to sauté until veggies are tender, about 5-7 minutes. Stir in chipotle peppers, cumin and potatoes.
Pour tomatoes and broth to the pot and bring mixture to a boil. Reduce heat to low and simmer for 25-30 minutes. Check for seasoning and adjust accordingly before serving with optional garnishes.