Add the vinegar, orange juice, mayonnaise, sugar, Dijon mustard, onion powder, salt, and pepper to a bowl or jar.
2 Tbsps white wine vinegar, 2 Tbsps fresh orange juice, 1½ Tbsps mayonnaise, 1 Tbsp granulated sugar, 1 tsp Dijon mustard, ½ tsp sea salt, ⅛ tsp onion powder, ⅛ tsp black pepper