Heat oven to 400° F. On a rimmed baking sheet, toss the tortilla strips with 1 tablespoon of the oil and ¼ teaspoon salt. Spread in a single layer and bake, tossing once, until golden and crisp, 7 to 10 minutes.
Meanwhile, in a large bowl, toss the shrimp with the cumin and ¼ teaspoon each salt and pepper. Heat 1 tablespoon of the remaining oil in a large skillet over medium-high heat. Cook the shrimp until golden and cooked through, 2 to 3 minutes per side.
In a large bowl, combine the orange and lime juices with the remaining 3 tablespoons of oil, ½ teaspoon salt, and ¼ teaspoon pepper. Add the romaine, cabbage, avocado, and shrimp and toss to combine. Serve the salad topped with the tortilla strips and pepitas.