From what I read
here, the Salesforce DB uses an Oracle database. Entity Framework
can use an oracle database.
From what I read in the first one, the migration from Salesforce to something that's under your control (assuming that the reason for the migration), could be a really big job. Note that it's not necessarily some standardized set of data. Your enterprise may have made several customizations to the standard data set. Perhaps a different approach could be to leave it where it is, use EF to access it and build the apps you want. Another possibility might be to use EF to create a 'code first from database'. Point it at the database you have in salesforce, have it generate the code-first implementation for you, switch the destination in web.config, and have that create the database in SQL Server.
If you want to get into more specific details feel free...
HTH,
Mike