In a small mixing bowl, whisk together lime juice, olive oil, cumin, chili powder, salt, and pepper until well combined.
Salad:
In a large mixing bowl, combine chopped romaine lettuce, drained and rinsed black beans, drained corn, diced avocado, diced red bell pepper, diced jalapeño pepper, chopped cilantro, cherry tomatoes and the crumbled queso fresco
Pour the dressing over the salad and toss until all ingredients are evenly coated.