Your best chances on a pier are a the Cabrillo Mole in Avalon or at Crystal Pier in San Diego. For most piers it's a fairly rare even to catch one from a pier. But, you don't need to spend thouands of dollars going to Baja, local boats (SD-LA) are currently catching yellowtails and tuna.
With the recent warm water (75 degrees in OC and nearing the 80s in San Diego), you may have a chance at Balboa pier or the oceanfront San Diego piers. However just because there is warm water doesn't mean there will be guaranteed yellowtail.
In the northern part of the country, freshwater anglers call Muskelunge "the fish of a thousand casts." Yellowtail from a pier is a rare and noble feat, indeed, akin to those big freshwater trophies sought in Wisconsin. As stated above, there are only a few places where yellows will visit. Several years ago, I released a 2 lb. bonito at the Catalina Mole that, upon hitting the water, did a weird convulsive death spin instead of zipping off for deeper water. Apparently, this was too much for an estimated 25 lb. yellowtail to watch... she swam out from UNDER the mole, did a couple of interested circles around the confused bonito, grabbed it like a dog bone about mid-body, and zoomed off through the kelp stringers to enjoy a big meal. We all stood, stunned, at what might have been if we'd had a 6/0 live bait hook and a 40 lb. kelp cutter rig pinned through the nose of that bonie....
All that to say, an active live bait (or a lure with a lot of action, like a Tady 45) stands a chance of attracting a yellowtail if one happens to be near the pier you're fishing. If you're willing to put the time in, use a sabiki to jig up some live bait (large sardines or 10-12" greenback mackerel would be ideal), and consider using a trolley rig, maybe with a small float and a leader of about 8-10 ft. Chances are, you'll catch a thresher shark before you catch a yellowtail, but that's not a bad alternative. Actually, chances are you'll catch nothing... but nothing ventured, nothing gained. Set your drag, fish with a strong clicker, and bring a comfortable chair and a good book.
Surface iron is a tough proposition from most piers, as the angle/height of the pier makes retrieving it through "the zone" tough, and unless you're an accomplished underhand caster, casting distance is limited.