Bring a large pot of water to a boil and cook pasta shells according to package directions, stirring occasionally until tender. Drain the pasta, then rinse under cold water until completely cooled for a firm, non-sticky texture (visual cue: cooled pasta).

In a cast iron skillet over medium-high heat, brown the ground beef, breaking it up as it cooks for even crumbles. Stir in taco seasoning and cook according to the package directions until the beef is evenly coated (visual cue: no pink and a thick taco-browned look).

Mix ranch dressing with salsa until smooth and slightly pink-red throughout (visual cue: uniform creamy color with no streaks).

In a large bowl, combine pasta, ground beef, cheddar cheese, cherry tomatoes, corn, black beans, and red onion (visual cue: an even spread of colors).

Pour the ranch-salsa dressing over the salad and toss until everything is coated (visual cue: glossy creamy coating clinging to pasta and beef).

Refrigerate the salad for at least 2 hours to let flavors meld and set up (visual cue: chilled and slightly thickened coating).

Top with crushed Doritos, lettuce, sour cream, and cilantro right before serving (visual cue: bright crunchy topping on top).