Can I use Visual C# express to produce commercial applications? And are there any other licensing issues.
Thank you
Yes, you can. From the product information page:
Visual Studio Express products are available at no charge and may be used for commercial, production usage subject to the license terms provided with each product. For example, you can use Express for Windows to create apps that you can then submit for sale in the Windows Store.
As for "other licensing issues" - you should probably download it and then review the EULA to see whether there's anything you deem to be an issue.