Warm Fajita Steak Salad

Name: Warm Fajita Steak Salad
Cuisine: Mexican
Ingredients: 1/2 cup olive oil; 1/3 cup freshly squeezed lime juice (from 2 to 3 limes); 1 teaspoon ground cumin; 1/2 teaspoon chili powder; 1/2 teaspoon kosher salt; Pinch cayenne pepper; 1 pound flank steak; 1/2 teaspoon ground cumin; 1/2 teaspoon paprika; 1 1/2 tablespoons olive oil; 1/2 medium yellow onion, thinly sliced; 2 medium red or orange bell peppers, thinly sliced; 1/2 teaspoon kosher salt, plus more for seasoning; 1/4 teaspoon freshly ground black pepper, plus more for seasoning; 1 medium romaine lettuce heart (about 8 ounces), chopped; 2 cups shredded red cabbage (from 1/4 small head of cabbage); 2 cups grape or cherry tomatoes, halved; 1 medium avocado, sliced