In a mixing bowl, combine 2 cups masa harina and 1/2 teaspoon salt. Add only 1 cup of the warm water and combine as much as you can using a spoon or spatula. Then I usually dump the mixture onto a work surface and add the remaining water (approx. 1/2 cup) a few tablespoons at a time, kneading the dough until it comes together into a cohesive ball. Set aside and cover with a damp towel until you need it.
If you're making the refried beans, start by peeling 2 garlic cloves and roughly chopping 1/2 onion. Cook the onion and garlic in a glug of oil over medium heat (you can leave the garlic cloves whole).
Once the onion is starting to brown, add 1 can beans (drained and rinsed), 2 chipotles in adobo, 1 tablespoon adobo sauce, 1/2 teaspoon cumin, 1/2 teaspoon salt, freshly cracked black pepper, and 1/2 cup stock (or water). Let simmer for a few minutes until heated through and then add everything to a blender, combining well.
Take a final taste of the beans for seasoning and heat. Add more salt if necessary, and if you want more heat you can add more chipotles (or adobo sauce).
Pull off a 3 oz. chunk of masa dough and use your hands to roll it into a ball. (3 oz. is somewhere between a golfball and a racquetball.)
Surround the dough ball in plastic (or a Ziploc bag) and use a flat-bottomed baking dish to flatten it to 1/4" thickness.
Pre-heat a dry skillet or comal to medium heat. Cook each side of the Sope until light brown spots are forming on the underside, approximately 2 minutes per side.
Once both sides are cooked, set aside to cool for a minute or so, then use your fingers to pinch up the edges to form an outer ridge. This will prevent the toppings from slipping off the Sope.
If you want to finish off the Sopes with a shallow fry, heat up a thin layer of oil in a skillet -- just 1-2 tablespoons will do the job. I use a thermometer to get the oil up to 360F, and this corresponds to a medium setting on my stove. Add the cooked Sope and shallow fry in the hot oil for 1-2 minutes or until the bottom side is brown and crispy. I usually put the beans on top while it's cooking to partially heat them up, but this is optional.
Top the Sopes with your choice of fixings. In addition to the refried beans, I topped them with Queso Fresco, diced Pickled Jalapenos, freshly chopped cilantro, and a squeeze of lime.
Serve immediately. This recipe will make 5-6 Sopes, depending on how thick you make them.