This are the tools you need to build SFML for Android on a Windows Machine
Make sure you've installed all tools (Tools -> Android SDK Tools / Platform-tools / Build-tools) in the Android SDK Manager.
If you have installed Visual Studio 2015 you might got some tools from above alerady. If so here are the default directories Visual Studio will put them:
C:\ProgramData\Microsoft\AndroidNDK (or AndroidNDK64)
C:\Program Files (x86)\Android\android-sdk
C:\Program Files (x86)\Microsoft Visual Studio 14.0\Apps
C:\Program Files (x86)\Java