You need to analyze your webpage to find out what is wrong in your webpage. There may be a number of issues like i) content not good enough ii) design of the site is not attractive iii) or you're targeting the wrong keywords etc.
Asking the owner or webmaster of that particular website to remove your link is the only way to delete the link. But as far as google webmaster tool is concerned, you can disavow unwanted links by uploading disavow links file in webmaster tools to neutralize their harmful effects in SEO but I'm...