how do you make beam weapons?
Johnoregan,
Beam weapons have been "created for us" by the developers of the game, check out any of several races, the advent are one, the tech another, or even of course the vasari craft, either the capitalships or the frigates of any of those races and you will find beam weapons as opposed to lasers, that you can use.
Either on the ships they are currently on, or on ships where you would like to copy them too.
Please keep in mind however, when i did this i thought to give all advent ships the beam weapons, and i thought it would be cool. It sorta was, however when i copied over the beam weapon lines from the capitalship to all the frigates i copied over the line in the antifighter that allows it to attack fighters. I didn't realize it at the time, but i did. and had a heck of a time with the enemy fighters after that...
haha... also keep in mind that many of the weapons for any craft can or are used in concert or harmony with the other weapons on the craft. By my generalizing them all to beams, i lost that nice harmony and used more antimatter quicker, some weapons i no longer had access to and some one-two punches that the original craft were set up for, i changed when i made everything a beam. haha... so while beams are indeed very cool.... there is sometimes a very cool reason to leave some ships the way they are. 
Just my two cents, take care and keep modding!
-Teal