Stir together the water and sugar in a small saucepan. Bring to a boil and add the walnuts. Boil for 2 minutes, then drain and place walnuts on a cookie sheet to dry.
Whip egg whites in a medium bowl until foamy. Stir in the mochiko until it has a pasty consistency. Heat the oil in a heavy deep skillet over medium-high heat. Dip shrimp into the mochiko batter, and then fry in the hot oil until golden brown, about 5 minutes. Remove with a slotted spoon and drain on paper towels.
In a medium serving bowl, stir together the mayonnaise, honey and sweetened condensed milk. Add shrimp and toss to coat with the sauce.