Blend together the buttermilk, mayonnaise, sour cream, cilantro, jalapeno, green onion, minced garlic, lime juice, cumin, oregano, sea salt, and freshly cracked pepper, to taste, using an immersion blender until well combined and creamy. Set aside to let the flavors mingle.
Place some chopped romaine in a serving bowl followed by grape tomatoes, diced avocado, green onion, pumpkin seeds, cotija cheese, and tortilla crisps. Drizzle the salad with the creamy cilantro dressing then toss to coat evenly. Serve immediately. Enjoy.