url: /_api/SPSiteManager/create
accept: application/json;odata.metadata=none
Content-Type: application/json;odata=verbose
method: POST

Body: 

     {
        "request": {
        "Title": "xiexinCommunication Site 2",
        "Url":"https://xxx.sharepoint.com/sites/xiexincommsite2",
        "Lcid": 1033,
        "ShareByEmailEnabled":false,
        "Classification":"Low Business Impact",
        "Description":"Description",
        "WebTemplate":"SITEPAGEPUBLISHING#0",
        "SiteDesignId":"6142d2a0-63a5-4ba0-aede-d9fefca2c767",
        "Owner":"xxx@xxx.onmicrosoft.com",
        "WebTemplateExtensionId":"00000000-0000-0000-0000-000000000000"}
    }