According to Kik Help Center, people that you delete won't be able to tell that you've deleted them. If you've deleted someone, your name will still appear in their list of contacts.
You also won't immediately be able to tell if you've been blocked by someone. If you've been blocked, you'll still be able to send messages to that person (you'll see a D beside your message) but they won't ever receive your messages (the D won't change to an R).
Kik is a mobile messenger platform for smartphones that allows users to exchange messages and place voice calls to other Kik users. Kik uses the phone's mobile data connection and is available for multiple platforms including iPhone, Android, Windows Phone and Blackberry.
Tip: Kik down? Find solutions to a number of problems that you might encounter using Kik messenger on Kik Help Center.