Remove stems and seeds from dried guajillo chiles and soak them in hot water for 10 minutes until softened.
Place the softened chiles, diced white onion, minced garlic, and 0.5 cup of chicken broth into a blender; process until completely smooth.
In a medium pot, combine the chile puree, remaining chicken broth, whole chicken breast, dried oregano, sea salt, and black pepper.
Bring to a gentle simmer over medium heat and cook for 20 minutes, or until the chicken is cooked through.
While the soup simmers, preheat your oven to 400°F. Lightly brush both sides of the corn tortillas with avocado oil and bake on a sheet tray for 4-5 minutes per side until golden and crispy.
Remove the chicken breast from the pot and shred it using two forks, then return the shredded meat to the broth along with the rinsed hominy.
Simmer for an additional 5 minutes to allow the flavors to meld and the hominy to heat through.
Ladle the pozole into a bowl and top with shredded cabbage and sliced radishes. Serve with the crispy tostadas and a fresh lime wedge on the side.