Assuming Mono is installed on all of your target machines then you can put together (manually) a .app package folder that will run your .exe file when a user double-clicks on it. There's a certain set of things you'll need to put in the .app package, one of which is a command shell file that will kick-off your .exe and will be executed when the .app is run.
B.t.w. Visual Studio Mac and Xamarin Studio and MonoDevelop are all basically different twists on the same thing, MonoDevelop. VS mac and XS have extras but the basic underlying IDE is MD. Whichever of these products you use to compile your code is unlikely to churn out anything different to the next.
The structure of the basic .app folder:
MyApp.app
+-- Contents
--- Info.plist
+-- MacOS
--- MyApp
--- MyApp.exe
+-- Resources
--- MyApp.icns
The contents are as follows:
Info.plist is a Mac OS specific XML file that contains a description of your .app package. It will look something like this:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>CFBundleDevelopmentRegion</key>
<string>English</string>
<key>CFBundleExecutable</key>
<string>MyApp</string>
<key>CFBundleIconFile</key>
<string>MyApp.icns</string>
<key>CFBundleIdentifier</key>
<string>com.myapp</string>
<key>CFBundleInfoDictionaryVersion</key>
<string>6.0</string>
<key>CFBundleName</key>
<string>My App Name</string>
<key>CFBundlePackageType</key>
<string>APPL</string>
<key>CFBundleShortVersionString</key>
<string>1.2.3</string>
<key>CFBundleSignature</key>
<string>xmmd</string>
<key>CFBundleVersion</key>
<string>1.2.3</string>
<key>NSAppleScriptEnabled</key>
<string>NO</string>
</dict>
</plist>
The MyApp.icns file is an icon file you want to use as the icon for your app package.
The MyApp.exe file is your compiled .NET exe.
The MyApp file is an executable command file that is executed when the .app package is executed by the user. This is referenced in the plist file under CFBundleExecutable and has to be executable (+x permissions, ). This is what it might look like:
#!/bin/sh
DIR=$(cd "$(dirname "$0")"; pwd)
MONO_FRAMEWORK_PATH=/Library/Frameworks/Mono.framework/Versions/Current
export DYLD_FALLBACK_LIBRARY_PATH="$DIR:$MONO_FRAMEWORK_PATH/lib:/lib:/usr/lib"
export PATH="$MONO_FRAMEWORK_PATH/bin:$PATH"
exec mono "$DIR/MyApp.exe"
Hope this helps. Cheers, Martin.