The phrase "shooting a smile at someone" means to briefly or quickly glance at someone while smiling. Perhaps "shot a glare in his direction" is more familiar?

Depending on the location of the comma, the speaker is either planning to make happy gestures at people, or killing people with a firearm which makes them happy.

To shoot a smile means to smile at someone. So the pun is that he is going to smile at every black person he sees.