In a medium bowl, add mayonnaise, ketchup, granulated sugar, garlic powder, and onion powder. Whisk until smooth.
Add rice wine vinegar, toasted sesame oil, and kosher salt. Whisk again to fully combine.
Gradually whisk in the water until the sauce reaches your desired consistency.
Cover and refrigerate for 30 minutes to 1 hour to let the flavors come together. Serve chilled or at room temperature.