Warm the vegetable oil in a skillet over medium-high heat. Place the shrimp in the pan and season with half of the salt, black pepper, cumin, oregano, garlic powder, and chili powder. Sauté the shrimp until they are just pink, approximately 3 minutes, then take the skillet off the heat.
In a large mixing bowl, combine the chopped romaine lettuce, cooked shrimp, diced tomatoes, minced jalapeño (if using), chopped red onion, minced cilantro, diced avocado, the remaining salt, and lime juice. Toss everything together until evenly mixed.
For a final touch, sprinkle tortilla strips on top, if desired.
Enjoy your fresh and flavorful salad!