Copy the link you want to go to, and enter that link into the search bar of your Chromebook, then stop. Do Search + ESC to open up the task manager, and find the Securly (the s icon) task. Right click on Securly, and very quickly end the task and press enter to open the webpage that you entered into the search bar, and you should be into the blocked website. Repeat for each blocked site you want to open.