Dynamic query using LINQ to SQL

I need to figure out if it is possible to dynamically build a query with LINQ, dynamically selecting the table in which to perform the query.

This is an example of what I would do:

//Not working,just for example

public List<dynamic> _getGenericList(String tableName)
    {
        var l = from a in db.//I need to use here tableName
                  select a;

        return l.ToList<dynamic>();
    }

Is there a way to make this possible?