For the dressing, whisk together the buttermilk, mayonnaise and lime juice. Add the remaining ingredients and whisk until smooth. Taste for seasoning. Refrigerate until ready to use.
Start a wood campfire and wait until the flames die down and the coals glow red with white ash. Place a grilling grate so that it sits above the coals and you have good, consistent medium-high heat.
Begin by deep-frying the tortilla strips. (This is easier to do over a camping burner than a campfire, as the oil temperature will come up faster and be more consistent.) In a medium pot, heat 2-3 inches of canola oil to 350° F over medium-high heat. Add the tortilla strips in batches and fry for 2-3 minutes, until crisp and golden. Drain on paper towels and season with salt. Set aside.
Lightly coat a cast-iron skillet with oil and set it over medium-high heat on the grate over the campfire. Add the garlic, onion and jalapeño, and sauté until softened and lightly caramelized, 5-6 minutes. Add the ground meat, tomato paste, paprika, cumin, oregano and chili powders, and brown the meat while breaking it up with the back of a large wooden spoon. Taste and season with salt and pepper. When the meat is cooked through, drain any excess fat from the skillet, add 1 cup water and reduce until the meat mixture has thickened slightly.
Assemble the salad with layers of sliced romaine, black beans, tomatoes, Cheddar cubes, radish slices, and tortilla strips. Pile on the warm meat mixture as the top layer to prevent the lettuce from wilting, and drizzle the salad with the ranch dressing. Garnish with sliced scallions, chopped cilantro, and crumbled Cojita.
Prep-Ahead Tip: Make the smoky ranch dressing 1-2 days before you head out camping and keep it refrigerated or chilled in a cooler until you need it. You can fry the tortilla strips 2-3 hours ahead of time, drain well and store in an airtight container. In place of the beef, you can substitute any leftover protein, such as smoked chicken, sliced tri-tip, brisket or ground turkey.