Combine chili powder, cumin, garlic and 3/4 teaspoon salt in a shallow bowl. Toss steak with seasoning, cover and refrigerate for at least 30 minutes.
In a small mixing bowl, whisk together sour cream, milk, green onion and remaining salt. Cover and set aside.
Heat 1 teaspoon of oil in a medium sized sauté pan over high heat. Add peppers and cook for 3-4 minutes until just tender and lightly charred. Transfer to a clean plate and set aside. Add 1 more teaspoon of oil to pan and sauté corn over medium-high heat for 2-3 minutes until golden, then transfer to a separate clean plate. Pour remaining oil into pan, and sauté seasoned steak over high heat for 3-4 minutes, stirring and turning occasionally until browned and cooked through. Transfer to a clean cutting board and chop into thin strips.
In a large mixing bowl, toss romaine lettuce with creamy cilantro dressing. Divide onto four plates. Top each plate of lettuce with consecutive strips of poblanos, steak, corn, California Ripe Olives, beans and cotija cheese and serve immediately.