Step 1: Remove stems and seeds from ancho and guajillo chiles. Place chiles in a heatproof bowl and cover with boiling water. Let rehydrate for 20-30 minutes, until soft and pliable.
Step 2: While chiles rehydrate, heat olive oil in a large Dutch oven or heavy-bottomed pot over medium heat. Add chopped onion and sauté until translucent and soft, about 5-7 minutes.
Step 3: Add minced garlic and jalapeño (if using) to the pot. Cook for 1-2 minutes until fragrant, being careful not to burn the garlic.
Step 4: Drain rehydrated chiles, reserving 1/2 cup of the soaking liquid. Transfer chiles to a blender along with fire-roasted tomatoes, chipotles in adobo, and a splash of reserved soaking liquid. Blend until completely smooth. Add more soaking liquid or chicken broth if needed to achieve a pourable paste.
Step 5: Pour the blended chile mixture into the Dutch oven with the sautéed aromatics. Add chicken broth, cumin, dried oregano, and bay leaf. Stir well. Bring to a gentle simmer, then reduce heat to low, cover, and cook for at least 20 minutes to allow flavors to meld.
Step 6: Stir in the shredded chicken, fresh lime juice, and chopped cilantro. Taste and adjust seasonings with salt and black pepper as needed.
Step 7: For the tortilla strips, heat 1/2 inch of vegetable oil in a skillet over medium-high heat. Fry tortilla strips in batches until golden brown and crispy. Drain on a paper towel-lined plate and sprinkle lightly with salt.
Step 8: Ladle hot chicken tortilla soup into bowls. Garnish generously with crispy tortilla strips, avocado, sour cream, cheese, and extra cilantro. Serve with lime wedges.