How can one remove all packages installed after a certain date/time?

Specific date %yyyy-%mm-%dd replace on here,

grep "2015-12-19.*.install " /var/log/dpkg.log | awk '{ print $4 }' | cut -d: -f1

You get a list of packages,

libck-connector0
libgssrpc4
libkadm5clnt-mit9
libkdb5-7
libkadm5srv-mit9
libgnutlsxx27
....
....

Append them to the list of Apt command arguments with xargs:

grep "2015-12-19.*.install " /var/log/dpkg.log | awk '{ print $4 }' | cut -d: -f1 | xargs sudo apt-get --yes purge

Incase you know the dates on which you installed these packages, the best way I've found to remove them automatically is the below command :

grep "2015-12-19.*.install " /var/log/dpkg.log | awk '{ print $4 }' | cut -d: -f1 

The above will list all packages installed on the date in the command. The final command is :

grep "2015-12-19.*.install " /var/log/dpkg.log | awk '{ print $4 }' | cut -d: -f1 | sudo apt-get remove -y

Replace the date to your needs and you should be good to go !