The La Jolla Playhouse has won this year's Tony Award for outstanding regional theater. Recommended by the American Theatre Critics Assn. and awarded by the Tony committee, the honor will be presented at the Tony ceremony June 6. In a separate award, the critics' association also is honoring a production opening next month at La Jolla, "Children of Paradise: Shooting a Dream," as the outstanding 1992 play produced outside New York and not yet scheduled for a New York opening. The play, created by the Minneapolis-based Theatre de la Jeune Lune, will be excerpted in the annual Burns Mantle Theater Yearbook along with its two runners-up, one of which was Sybille Pearson's "Unfinished Stories," produced at the Mark Taper Forum last year.