Heat one tablespoon of the olive oil in a large (12 inch) cast iron skillet or sauté pan over medium heat. Add half of the onion (3/4 cup) and the poblano pepper. Sauté the onion, stirring frequently, for 5 minutes, or until the onion is clear. Add garlic and sauté for another minute. Add the black beans and sauté them for 1-2 minutes more, or until the beans are warmed through.
Transfer the beans to a food processor fitted with the S blade. Add lime juice, 1/4 cup water, 1/2 teaspoon ground cumin, and 1/2 teaspoon salt. Pulse the beans until they’re mostly smooth, but some whole or partial beans and overall texture remain (you don’t want this to be as smooth as hummus). Season the bean mixture to taste with extra lime juice, cumin, or salt and set aside until you’re ready to assemble the hues rancheros.
Using the same skillet, heat the remaining tablespoon olive oil over medium high heat. Add the remaining chopped onion (another 3/4 cup). Cook the onion, stirring frequently, for about 3 minutes, or until it’s turning clear. Add the cauliflower pieces and spread them out evenly in the pan. Allow them to sizzle and cook for 4 minutes, or until the pieces are lightly browning on the bottom. Give the cauliflower a stir and allow it to continue browning (the onions will brown a bit, too, and that’s OK!) for another 3-4 minutes, or until the cauliflower is tender and crispy on the outside.
Reduce the heat to medium low. Mix together the remaining teaspoon cumin, the chili powder, smoked paprika, and cayenne pepper. Sprinkle this spice mix over the cauliflower pieces and stir well to coat the cauliflower evenly with the spices. Sprinkle the cauliflower with the remaining 1/4 teaspoon salt and a pinch of cayenne pepper, if desired. Stir in the diced tomatoes. Mix everything well, taste, and adjust the seasonings (more salt, chili, etc.).
To assemble the huevos rancheros, gently toast each corn or wheat tortilla over an open burner on the stove. You should use a low flame, watch the tortilla carefully, and flip after about a minute, or until the side you’re toasting is getting nice and crispy. Repeat on the other side, and with all of the remaining tortillas.* Spread each tortilla with about a quarter cup of the refried beans, a half cup of the cauliflower and tomatoes, and whatever toppings you like. Enjoy!
*If you don't feel like toasting the tortillas one at a time, you can simply preheat the oven to 275 before you start cooking, wrap all of your tortillas in foil, and keep them in the oven until you're ready to assemble and serve.