Add the vidalia onions, garlic and ginger to the pan and sauté them to a golden brown. Add the curry powder and dry mustard, mix well and cook for 30 seconds. Do not burn. Remove the pan from the heat and cool the onion mixture to room temperature or cooler.
Combine the cooled onion mixture, lime juice, rice vinegar and salt into a food processor. Blend well.
Place the mixture into a stainless steel mixing bowl. Refrigerate to cool.
When the mixture is cooled, blend in the chilled mayonnaise and adjust the salt if needed.
Place the curried mayonnaise into a storage container with a lid. Refrigerate for 1 hour before use.