Here's a handy function you can add to your .bashrc to open Windows explorer directly from a WSL terminal session:
function e()
{
path=$1
if [ -z "$path" ]; then
path="."
fi
explorer.exe $(wslpath -w $path)
}
Usage:
# If you don't provide a parameter, it'll open in your current directory
$ e
# Or provide a path to the desired directory
$ e path/to/directory
This makes use of the wslpath command more info here