Preheat oven to 350° F. Brush the tortillas on both sides with 1 teaspoon of the oil and cut lengthwise into 1/4-inch-wide strips. Place on a baking sheet. Sprinkle evenly with 1/4 teaspoon of the salt and the chili powder and bake for about 12 minutes or until crispy. Meanwhile, over medium heat, cook the beef in a large nonstick skillet. Stir in the salsa and beans and keep warm over medium-low heat. Combine the lettuce, cilantro, and tomatoes in a large bowl. Whisk together the lime juice and the remaining salt and oil and toss with the lettuce mixture. Place the lettuce mixture in 4 shallow bowls. Place the warm beef mixture over the lettuce and top with the sour cream, Cheddar, avocado, green onions, and tortilla strips.