1. Cook taquitos in microwave according to package directions.
2. While taquitos are cooking, drain and thoroughly rinse beans in a colander. Allow to drain completely.
3. Cook corn in a microwave-safe bowl on HIGH (100% power) for 2 1/2 minutes.
4. Prepare tomatoes, onions, and cucumbers.
5. Cut taquitos into 1" pieces.
6. Mix all ingredients, except taco sauce and lime juice, together in a large bowl.
7. Add taco sauce and lime juice and mix well.