Step 1

First, prep the spicy tomato sauce: Peel and finely chop 1 medium white onion; set aside ½ cup for serving. Transfer half of remaining chopped onion to a large saucepan (you’ll use the rest of the onion for the beans). Peel and finely chop 4 garlic cloves. Transfer to saucepan. Finely chop 1 chipotle chile and transfer to saucepan. (You can store any remaining chiles individually in the freezer to use for later.)

Step 2

Add 1 15-oz. can fire-roasted tomatoes, 2 Tbsp. chili powder, and 2 Tbsp. adobo sauce (use 1 Tbsp. if you're sensitive to heat) to saucepan, stir to combine, and bring to a boil over medium-high heat. Nestle 2 skin-on, bone-in chicken breasts into mixture, reduce heat to medium-low, and bring liquid to a simmer. Cover saucepan and cook until chicken is cooked through and shreds easily with two forks, 25–35 minutes.

Step 3

Meanwhile, make the beans: Slice 4 oz. smoked bacon into thin strips about ¼" wide and transfer to a large skillet. Add remaining chopped onion and cook over medium heat, stirring occasionally, until fat has rendered, bacon is crispy, and onion is browned and tender, 8–10 minutes.

Step 4

Increase to medium-high and add 2 15-oz. cans black beans and their liquid (that's right—don't drain them!). Bring to a boil and cook, stirring occasionally, until liquid is reduced slightly, about 5 minutes.

Step 5

Using a potato masher (or a wooden spoon, if you're in a pinch), smash beans until almost no whole beans remain and mixture is thick, smooth, and creamy, like the consistency of sour cream. Remove from heat, taste and season with salt if necessary, and let cool slightly; the refried beans will thicken as they sit.

Step 6

When chicken is finished cooking, use tongs to transfer to a plate and let cool slightly. While chicken cools, increase heat to medium-high and simmer sauce, uncovered and stirring occasionally, until it looks like a thick and chunky salsa, about 5 minutes. Let cool slightly in pan.

Step 7

Remove skin from chicken breasts and separate meat from bones; discard skin and bones. Shred meat into small pieces and transfer to a medium bowl. Pour warm salsa over chicken, season with 1½ tsp. salt, and toss to coat.

Step 8

Assemble your tostadas: Use your hands to crumble 4 oz. queso fresco into small pieces (about the size of dried lentils).

Step 9

Spread about ⅓ cup refried beans over 1 tostada. Top with about ½ cup chicken tinga.

Step 10

Repeat with as many tostadas as you think you’ll eat (the separate components will keep well in the fridge). Top with queso fresco, cilantro, and reserved chopped onion.