A family of Microsoft suites of integrated development tools for building applications for Windows, the web, mobile devices and many other platforms. Miscellaneous topics that do not fit into specific categories.
Linq to SQL should be available in VS 2015. I do not think the tools are installed by default. You will have to run the installer and install the tools. Please note the entity framework is the recommend to be used over linq to sql
https://learn.microsoft.com/en-us/dotnet/framework/data/adonet/ef/getting-started