I tried to make \'Hello World\' in Rust using this tutorial, but the build command is a bit verbose:
cargo +nightly build --target wasm32-unknown-unknown --relea
You could use a Cargo configuration file to specify a default target-triple for your project. In your project's root, create a .cargo directory and a config file in it with the following contents:
.cargo
config
[build] target = "wasm32-unknown-unknown"