How can I open the User Account Control settings from command line

C:\Windows\System32\UserAccountControlSettings.exe

I assume you are looking for the command to open the User Account Control applet from the Windows Run command. To do this, in the Run box type useraccountcontrolsettings then click OK to get directly to the User Account Control Settings window.

You can also enable and disable via CMD:

Disable:

C:\Windows\System32\cmd.exe /k %windir%\System32\reg.exe ADD  HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v  EnableLUA /t REG_DWORD /d 0 /f

Enable:

C:\Windows\System32\cmd.exe /k %windir%\System32\reg.exe ADD  HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v  EnableLUA /t REG_DWORD /d 1 /f