Wingers Stuart Green and Stuart Elliott, who scored twice, did the damage.
Green broke through after only nine minutes with a spectacular 25-yard volley after Elliott's shot had been blocked.
Elliott made it 2-0 in the 19th minute, scoring from 15 yards after Torquay's Bertrand Bossu had parried Nick Barmby's shot. And Elliott hit his second in the 57th minute, firing home from 22 yards with his left foot.
The Northern Ireland international also hit the post going for his hat-trick in the 73rd minute.
Torquay dominated territorially and had possession for long periods, with Alex Russell outstanding in midfield, but they had little to offer up front.
They needed to pull a goal back before half time, but they missed two great chances. Substitute Tony Beddow headed wide at the far post when he should have scored from a Russell cross, and Boyo Akinfenwa hit the bar with a close-range header from Bedeau's cross just before the interval.
The home side created more strong pressure early in the second half, but Elliott's second goal snuffed out any hope of a fightback.
A highly entertaining contest was marred six minutes from time by a double sending off. Hull sub Aaron Wilbraham and Torquay captain Craig Taylor appeared to clash in an off-the-ball incident, and referee Lee Cable sent them both off. Taylor had been booked moments earlier.
Hull now travel to Port Vale on Saturday with a clean sheet from their opening 180 minutes of league football.
Although Green and Elliott took the honours up front, City's centre backs Leon Cort and Damien Delaney were outstanding.
Hull manager Peter Taylor said: "What pleased me most was that we didn't let Torquay play too much.
"We knew what a good side they were after they beat us at our place last year and we were looking for revenge.
"I don't think their goalkeeper had a chance with any of our goals. We've got players capable of scoring great goals, and they showed that tonight."
Torquay head coach Leroy Rosenior said: "Hull's finishing was cracking. It was a great away performance by them.
"When they got their chances, they took them. When we got ours we didn't. That was the difference.
"People may wonder why I'm not too upset at losing 3-0 at home but we played some great stuff at times and the lads never gave up.
"It was one of those days when everything seems to go against you."