When you're using Curiosity for searching, we'll remember which results you've opened for you - don't worry, this is also only visible to your user.
You can access this by clicking on the menu button and then in Recent:
You'll see on the left side your search history and a quick access to your Bookmarks, and on the right side all items that you have interacted with in your search:
Removing a search from my Search History
If you would like to delete a saved search from your history, right click on it and click on the Forget search option:
Removing a Bookmark
Right click on the item you would like to remove and click on Remove bookmark: