It is pretty easy to do both Lightning Strikes
and I can see you
at the same time.
What you need is the Hookblade (for Double Assassinations), Cherry Bombs and of course Smoke Screens. Now find a bigger group of enemies. The video below shows you one possible spot. I'll also give you another one which is perfect for this.
Get close to the group and lure them all together with a Cherry Bomb. Once they are close enough blind them with a Smoke Screen. Now is the time to move in and hammer
for some kills.
Here the video mentioned above:
Video credits to PowerPyx
And here as promised the spot I found to be very good:
Image credits to jeuxvideo.com
In the lower left corner of the map you'll have a Synchronisation Point. Close to that one you'll see a small stationary group of guards under an arch and a patrol. As soon as the patrol is close to the stationary group use the Cherry Bomb and Smoke Screen. This will give you way more targets than you actually need.