Quick-soak the beans: place rinsed black beans in a large dutch oven and add water until it covers the beans by an inch or so. Bring to a boil for 2-3 minutes, then turn off the heat, cover, and let sit for 1 hour. Transfer the beans, and enough liquid to just reach the top of the beans, to a bowl and set aside. Clean out the pot and return it to the stove.
Add the olive oil to the pot and heat to medium-high. Once hot, add the onion, bell pepper, and poblano pepper and cook until softened, about 5-7 minutes. Add the garlic and cook until fragrant, about 1 minute longer. Stir in the seasonings and cook for 30 seconds.
Carefully pour in the vegetable broth, followed by the beans and their cooking liquid. Stir well, then bring the mixture to a boil. Reduce the heat to low and let simmer, covered, for 2 hours, or until the beans are soft and can be mashed against the side of the pot easily with the back of a spoon.
Before serving, in a medium-sized bowl add the tomatoes, cilantro, ½ of the queso fresco, and the juice from ½ lime. Toss together then season with salt and pepper and set aside. Heat a large skillet over medium-high heat and add 2 teaspoons of olive oil. Once hot, add the red onion and corn and cook, stirring occasionally, until the onion is soft and corn is beginning to brown, around 10 minutes. Remove pan from heat and stir in mayo, remaining queso fresco, chili powder, the juice from ½ lime, and a sprinkle of salt and pepper as desired. Scoop heaping portions of creamy street corn onto each bowl of soup and garnish with the tomato salad mixture.