Burst lasers go pew-pew-pew, and pulse lasers go pew, pew, pew...
Burst lasers fire 3 shots per trigger pull, pulse lasers are 1 shot per pull. The only way they would continuously fire is if you have turrets (versus gimble or fixed).
For the kill-warrant scanner, you have to be in range and hold the trigger with the target in your sites for the complete scan (5 seconds I think). There will be a little blue bar on your HUD for the fire group that fills up and says "complete", and there will also be a "V" that completely closes when you finish the scan.