How to access encrypted Ubuntu 16.04 files from Windows 10 in a dual boot system?

Since there are two methods that you could have used (independently or in combination) to perform encryption, I'll touch on both separately. And then I'll address access from Windows.

You could have encrypted your entire disk with LUKS like this during install

Or you could have encrypted your home directory with ecryptfs like this during install

Disk encryption with LUKS

If you encrypted your entire disk with LUKS, you may want to look into a program for Windows called LibreCrypt. I have used it with success in the past to access LUKS encrypted partitions from Windows 7.

Home directory encryption with ecryptfs

If you encrypted your home directory, there is currently no way to get at this from Windows. However, it is possible to remove the home directory encryption so long as you have enough disk space to make a duplicate of your home directory.

Accessing the Linux ext2/ext3/ext4 filesystems from Windows

Now, in theory, all you should need to do is mount your Linux file systems in Windows. I've not tried it, but supposedly, Ext2Read should enable you to mount ext2/ext3/ext4 filesystems in Windows. Furthermore, it is said to support LVM2 which will be important if you chose to use LVM when you installed.