In a small bowl, whisk together the sour cream, salsa, 1 tablespoon of the chopped cilantro, 1 1/2 teaspoon of salt, and 1 1/2 teaspoon of the taco seasoning. Stir until smooth and creamy, then set it aside to use as the dressing.

Preheat your grill to high heat (around 450°F to 500°F). In another small bowl, mix the canola oil with the remaining taco seasoning. Pat the steak dry with paper towels and sprinkle both sides evenly with the remaining 1 1/2 teaspoon of salt.

Brush the steak with some of the oil-seasoning mixture, then place it on the hot grill. Cook with the lid closed for about 10 to 13 minutes or until it reaches your preferred doneness (135°F to 145°F for medium). Flip the steak halfway through and brush both sides with the remaining oil mixture as it grills. Once done, transfer the steak to a cutting board, tent it with foil, and let it rest for 10 minutes.

While the steak rests, if you're using fresh corn, grill it until lightly charred and tender, about 10 to 12 minutes, turning occasionally. Once cool enough to handle, slice the kernels off the cob.

Slice the steak thinly against the grain, then cut the slices into bite-sized pieces.

Add the salad greens to a large serving bowl or divide them among individual bowls. Sprinkle with the remaining 1/2 cup of cilantro. Layer on the steak, corn, shredded cheese, crushed tortilla chips, tomatoes, pickled onions, and avocado.

Drizzle with the dressing as desired, garnish with extra cilantro, and serve the remaining dressing on the side.