or you go KLINGON, 90% of their ships can equip dual cannons...doesn't make allways sense, but they can.
Anyway, to actually make use of dual cannons you need atleast a base turnrate of 9 or10...the more the better of course.
Look for something like 'can take cannons' in the shipyard listing Fed side (for some reason KDF doesn't have text indicating whether a ship can ATM). Fed side is limited to mostly escorts with a few exceptions, the new Vesta Science ship can take them and the old Galaxy-X Dreadnought can take them as well (though it has a slow turnrate and limited Tac BOff spots). All ships can fit single cannons, turrets, beam arrays and dual-beam banks.
The BOff ability you want is called 'Cannon Rapid Fire' to spew out the weapon bolts with cannons.