Place the chicken breasts in a large pot and cover with cold water. Add one of the onion halves, 2 garlic cloves and 1 t kosher salt. Bring to a boil over high heat, skimming and discarding the foam that rises to the top. Reduce heat and simmer until the chicken is firm to the touch, about 30 minutes. Remove chicken from broth and set aside to cool. Do not throw the broth way! Once chicken is cool, shred the meat with your hands and discard the skin and bones.

While chicken is simmering, place tomatoes, 2 garlic cloves, chipotles and 1/2 t salt in a blender and blend until smooth. Slice the remaining onion half into thin half moons. Heat the olive oil in a large skillet over medium high heat and add the onion, thyme and a large pinch of salt. Cook, until the onion just begins to soften, stirring occasionally.

Add the shredded chicken and the tomato mixture to the skillet along with 1 c of the reserved broth. Bring the mixture to a boil, reduce the heat and simmer until the chicken is very tender and the flavors have developed, about 20 minutes. Keep warm until ready to assemble tostadas.

Refried Beans

Fry bacon. When bacon is crisp, remove from pan, but leave the bacon drippings. You can garnish the beans with the crisp bacon or you can eat it as is! Add garlic and onion and cook until soft. Add beans and cook until warmed. Using a potato masher or a fork, mash the beans. I prefer them to have some texture, but that is up to you. You may want to thin the mixture with some chicken broth, depending on how thick you like your refrieds! Season with oregano and cumin and add salt as desired.

Tostadas

In a skillet that can hold the tortillas, heat about 1″ of oil over medium high heat. Once the oil is hot, add the tortillas in one layer. (I usually do one at a time, but you can do s many as your skillet will hold.) Press each tortilla sown with tongs or a spatula to keep them flat. Cook until browned and crisp, about 1 minute per side. I do not like them totally crisp because then the don’t break as easy when you add your toppings. As they are cooked, transfer to a paper towel lined plate and blot each side. Set aside until ready to use.

To assemble:
Spread tostada with about 2 T of refried beans. Top with a large drained spoonful of chicken tinga, a bit of lettuce, some diced tomato, some crema and a bit of cheese. Garnish with cilantro.