Grate cucumbers into a medium bowl. Toss with rice vinegar, salt, and 1/2 tsp. garlic salt. Cover and chill 8 hours.
Drain cucumber mixture well, pressing between paper towels.
Beat cream cheese, mayonnaise, and remaining 1/2 tsp. garlic salt at medium speed with an electric mixer 1 to 2 minutes or until smooth. Stir in cucumber mixture and chives. Cover and chill at least 1 hour.