No experience w/ tuna up here, but in Hawai'i I've done it a lot. Look for a "boil" (suface feeding) and birds. That's where you want to troll. They will be eager to bite. Plugs, rubber skirts etc will work. They love pink, lime green, tow-toned silver/blue (back home at least)...Live bait thrown out to keep the school at the surface is effecient, if you have the bait.
As Roger said, we also used hand line gear/technique. Rig consists of cording stuffed into 1-2' of surgical tubing (so the tubing can stretch but will only go as far a cording) and secured on each end with a tight wrap of cordage. Same cording goes out behind the boat to a swivel. From swivel back is mono with the rubber skirt/hook. We ran two of these center, close to the boat however, with two more rods outboard and two more on out riggers to form the "V". Love tuna fishing! And keep the heads if you crab...there is NO better bait than Aku/Kawakawa/Tombo Ahi* heads/gills. Nice and bloody and oily.
*Aku=skipjack tuna & Kawakawa=mackarel tuna & tombo ahi=albacore