In a small saucepan over medium heat, combine water and sugar until dissolved. Bring to a boil and cook until slightly reduced and thickened.
Add walnuts and cook for about 2 to 3 minutes. Remove walnuts and arrange in a single layer on a parchment-lined baking sheet to cool and dry.
In a wide pan over medium heat, heat about 2-inch deep of oil.
In a bowl, whisk egg whites until foamy. Slowly add cornstarch and whisk together to form a batter.
Season shrimp with salt and pepper to taste. Dip shrimp one by one into the cornstarch batter to fully coat.
Add to hot oil and deep-fry until lightly browned. With a slotted spoon, remove from pan and drain on a wire rack.
In a bowl, combine mayonnaise, condensed milk, and honey. Stir until smooth.
Add fried shrimps and gently toss in sauce to coat.
Transfer to serving platter and garnish with candied walnuts.