The 20th-anniversary season of the Universal Amphitheatre will be highlighted by the grand opening of the new CityWalk entertainment complex and the return of “Jesus Christ Superstar.”Larry Vallon, executive VP of MCA Concerts, announced the 1993 season yesterday. Tickets for the events are on sale by mail and phone beginning Sunday. Vallon said yesterday that CityWalk will be open in late May. “Jesus Chris Superstar,” featuring original cast members Carl Anderson and Ted Neeley, returns for a June 1-6 run. It ran 11 weeks at Universal the summer of 1973. Sked is not the complete list of acts. Shows are scheduled by Jackson Browne, Lynyrd Skynyrd, Carole King, The The and Robert Plant, but no dates are confirmed. Patti LaBelle kicks off the season May 14 and 15, followed by Grand Slam Jam ’93, teaming John Kay & Steppenwolf, Poco, Dave Mason and Edgar Winter (20). June opens with “Jesus Christ Superstar” (1-6). Also due that month are Lee Ritenour (16), the Temptations and Four Tops (17), Dwight Yoakam (18), Louie Anderson (24), Willie Nelson and Family (25), and Ana Gabriel (26, 27). July finds the Smothers Brothers with Glen Campbell and Fritz Coleman (10), with Little Richard (17), Arlo Guthrie (21), Dennis Miller and Rita Rudner (23), Lyle Lovett & His Large Band (24), the Association, the Buckinghams, Gary Puckett and Gary Lewis & the Playboys (30), and the Def Comedy Jam (31). August finds Kenny Loggins (14, 15) as the only currently scheduled attraction. September is led by Foreigner (9), followed by Gary Valenciano (10), Howie Mandel (11), Vince Gill (17), and Fred Penner & the Cat’s Meow Band and Norman Foote (26). October has Juan Gabriel (1, 2, 3), Peter Nero & the American Pops Orchestra (8), Billy Ray Cyrus (15), a Salsa Fest starring Celia Cruz (16), and Midnight Oil (19). In November, Grover Washington Jr. stops in (7), followed by Sawyer Brown and Chris Le Doux (13), Tom Jones (18), Spyro Gyra (19), Vicente Fernandez and Alejandro Fernandez (20, 21), Julio Iglesias (24, 26), and Ricky Van Shelton, Lorrie Morgan and Sammy Kershaw (30). Capping the year is Barry Manilow, in from Dec. 27-30. Manilow also has the first Universal date of 1994, scheduled for Jan. 1.