Sweat onions in oil on medium heat until opaque. Add rice; cook about 1 min., stirring to evenly coat with oil. Stir in wine; cook until absorbed. Gradually add 1/3 of the chicken stock, stirring constantly until almost all the stock is absorbed. Repeat with the next 1/3, then the last 1/3; cook until desired consistency.
Fold in the seafood; cook until done. Quickly mix in the butter and cream cheese, then stir in the Parmesan, salt and pepper.
Spread mixture onto 2 half-sheet pans and refrigerate at least 2 hours (or overnight) or until firm.
Use 2-1/2-inch-round cookie cutter to cut rice mixture into 50 cakes; place in parchment paper-lined sheet pans and refrigerate until firm.
Combine the cracker crumbs and bread crumbs; press each cake firmly in the crumb mixture, turning to evenly coat all sides.
For each serving: Cook 1 risotto cake in 1 tsp. oil, turning until both sides are golden brown. Spoon about 1 Tbsp. vinaigrette onto serving plate; top with cake.