Как каждый повторно запускает Средство поиска программно?

Send it a quit event using AppleScript, then send it an activate event:

//tell Finder to quit
NSAppleScript *restartFinder = [[NSAppleScript alloc] initWithSource:@"tell application \"Finder\" to quit"];
[restartFinder executeAndReturnError:nil];

EDIT: add a delay to make sure Finder is ready to receive an activate event. On my machine, sometimes it needs this delay, sometimes it doesn't:

//delay 1 second
restartFinder = [[NSAppleScript alloc] initWithSource:@"delay 1"];
[restartFinder executeAndReturnError:nil];

(...end EDIT)

//tell Finder to activate
restartFinder = [[NSAppleScript alloc] initWithSource:@"tell application \"Finder\" to activate"];
[restartFinder executeAndReturnError:nil];