Example: delete List Item

Example.DeleteListItem.cs

using (var client = new SPHttpClient(webUri, userName, password))
{
    var listTitle = "Tasks";
    var itemId = 2;
    var endpointUrl = string.Format("{0}/_api/web/lists/getbytitle('{1}')/items({2})",webUri,listTitle,itemId);
    var headers = new Dictionary<string,string>();
    headers["IF-MATCH"] = "*";
    headers["X-HTTP-Method"] = "DELETE";
    client.ExecuteJson(endpointUrl,HttpMethod.Post,null,headers);
    Console.WriteLine("Task item has been deleted");
}