Flak suppression via strafing was widely employed over sea and land; I'm afraid I haven't much on the Pacific theater, and nothing from the perspective of those being strafed, but the Strike Wings of RAF's Coastal Command were key exponents of the technique.

As German coastal convoys became increasingly well protected by escorts with heavy anti-aircraft armament, low-level attacks by small numbers of aircraft suffered heavy losses. The RAF turned to the Beaufighter heavy fighter as the solution; with four cannon, six machine guns and a pair of bombs it was well equipped to attack escorts and suppress flak. Other Beaufighters exchanged the machine guns and bombs for a torpedo, giving them their 'Torbeau' nickname, for attacking the larger merchant ships in the convoys. The first Beaufighter wing, based at North Coates, flew its first mission in November 1942 with poor results, sinking a small tug for the loss of three aircraft including the Wing Leader. A replacement Wing Commander, 'Nebbie' Wheeler, spent the next five months training the squadrons to work together and developing tactics, including:

"2) The anti-flak sections must protect the Torbeaus from enemy fire. Where possible, three cannon-firing Beaufighters should be detailed to attack each escort in the convoy. All their diving angles should be simultaneous but from slightly different angles, synchronized to confuse the enemy gunners and keep their heads down at the time when the Torbeaus were flying in steadily at low level to drop their torpedoes and sink the merchant vessels."

The next attack in April 1943 was a great improvement, sinking a 5,000 tonne cargo ship and damaging several escorts for no losses. From June 1943 the Beaufighter's armament was augmented by eight 3" Rocket Projectiles (RPs) with either explosive or armour-piercing warheads; further Strike Wings were formed with Mosquitos joining the anti-shipping missions in 1944.

It's safe to say convoy attacks were pretty unpleasant for both sailors and aircrew. The ships were armed with anti-aircraft guns from 20mm to 105mm, putting up tremendous volumes of flak, while the gun positions had little protection for those on the receiving end of strafing. Accuracy wasn't pinpoint; during a convoy attack shortly after D-Day 42 Beaufighters of the North Coates and Langham wings sank two merchant ships and damaged all seven of the escorting minesweepers. Casualties from the convoy were nine dead, one missing and seventy wounded; the ships fired 206 105mm shells, 35 37mm shells and 5,044 20mm shells, damaging several of the attackers but not bringing any down. The psychological effect was certainly strong both ways, forcing the aircraft to manoeuvre rather than carefully line up attacks, and an author on the Strike Wings mentions that "Beaufighter airmen would sometimes see the ships' gunners dive over the side rather than face those burning projectiles converging towards them". (The Strike Wings: Special Anti-Shipping Squadrons 1942-1945, Roy Conyers Nesbit.)

I'm not sure about Peal Harbor for getting an idea, but there's a fair amount of media of the Strike Wings such as 'Sperrbrecher 102' under combined rocket and cannon fire; Bristol Beaufighters rake trawler escort vessels with cannon fire; The flak ship Vp1605 MOSEL engulfed in a torrent of fire from Beaufighters; A De Havilland Mosquito firing on two moored merchant vessels with rocket and cannon fire. Pathé Films also have a couple of newsreels with footage of attacks, Coastal Command Strikes At German Convoy and the second half of RAF Operations By Bomber And Coastal Command.