You wouldn't use Chilkat to receive the information contained in the POST sent to your ASP page. You would just use ASP for that.
In general, however your web page is implemented (Classic ASP, ASP.NET, PHP, Perl, Python, Ruby, etc.) you would use that language's features to collect the incoming POST information.
At that point, you might use Chilkat, if appropriate, for anything. For example, you might use Chilkat's JSON classes to parse the received JSON.
In Classic ASP, you might begin by examining the incoming data:
<html>
<body>
<%
for each x in Request.Form
Response.Write("<br>" & x & " = " & Request.Form(x))
next
%>
</body>
</html>