Salt Cloud needs, at least, one configured Provider and Profile to be functional.
To create a VM with salt cloud, use command:
salt-cloud -p <profile> name_of_vm
Assuming there is a profile configured as following:
fedora_rackspace:
    provider: my-rackspace-config
    image: Fedora 17
    size: 256 server
    script: bootstrap-salt
Then, the command to create new VM named fedora_http_01 is:
salt-cloud -p fedora_rackspace fedora_http_01
To destroy a created-by-salt-cloud VM, use command:
salt-cloud -d name_of_vm
For example, to delete the VM created on above example, use:
salt-cloud -d fedora_http_01