By default, all links and hyperlinks in Blogger opens in your current window. If you to force links in Blogger to open in new tab, then this tutorial is for you. I also have a tutorial that explains the ways to add Facebook like box to blogger.
Force Links In Blogger To Open In New Tab
1. Login to your Blogger account
2. Navigate to TEMPLATE > Edit TEMPLATE
3. Search for the <head> tag in your template’s code.
Hint: Use Ctrl+F to find the code.
4. Copy the code below and Paste it below the tag
5. Hit the save button and you are done.
This is how you force links in Blogger to open in new tab. I hope this tutorial was helpful, here is another guide that will show you how to remove blogger sidebar and create a full width page. You definitely want to check it out.