Make the creamy dressing. Combine all dressing ingredients except the buttermilk in the bowl of a food processor. Blend until completely smooth, scraping down the sides as needed.
Finish with buttermilk. Transfer to a bowl, whisk in the buttermilk, then taste and adjust seasoning. Store in an airtight container in the refrigerator until ready to use.
Make soft-boiled eggs. Bring a large pot of water to a rapid boil. Add a generous pinch of salt and a splash of white vinegar. Set a timer for exactly 7 minutes, then carefully lower the eggs into the boiling water.
Prepare the ice bath. Fill a large bowl with cold water, then add 1 cup of ice cubes. When timer goes off on the eggs, immediately transfer to ice bath. Cool for 10 minutes before gently peeling eggs.
Season the chicken breasts with half the ground cumin, chili powder, and Kosher salt, rubbing it onto all sides. Allow this to sit out at room temperature while you continue.
Sauté the corn and beans. Heat 2 Tbsp olive oil in a large skillet over medium-high heat. Add shallots and cook until translucent, about 2-3 minutes. Add corn, drained black beans, jalapeño, remaining cumin, chili powder, and Kosher salt. Cook until corn is tender, but not too soft, about 3-4 minutes. Squeeze half a fresh lime on top, then stir, taste, and adjust seasoning as needed. Transfer to a bowl.
Cook the chicken. To the same skillet, add 2 Tbsp olive oil, then warm over medium-high heat. When not, add chicken, then cook for 5-7 minutes per side, or until an internal temperature of 165°F (74°C) is reached. Cook time will depend on thickness of the chicken breasts. Let chicken rest for a few minutes before slicing.
Prepare remaining salad ingredients. Roughly chop or hand rip lettuce into small bite-size pieces. Chop tomatoes into a medium dice, about ½-inch pieces. Peel and cube the avocado. Crumble the queso fresco into small bite-size pieces.
Assemble the Mexican Cobb salads. Place a layer of lettuce in a bowl or plate as the base layer of your salad. Starting from the top of the bowl and working your way down in neat lines, layer each prepared ingredient: avocado, sautéed corn and beans, cooked chicken, crumbled bacon, chopped tomatoes, and queso fresco. Add one halved soft boiled egg to each plate, a lime wedge, and some fresh cilantro (chopped or left whole)
Finish and serve. Drizzle each salad with avocado lime ranch, then top with a generous pinch of flaky sea salt. Serve immediately or at room temperature. Enjoy!