1 pound small carrots, cut into 2-inch lengths
2 tablespoons lemon juice, plus wedges for serving
1 tablespoon olive oil
1½ teaspoons toasted sesame seeds
1 teaspoon ground cumin
Kosher salt and black pepper
1 pound skirt steak, cut into 4 pieces
12 corn tortillas, warmed
1 avocado, sliced
Watercress and sour cream, for serving