Cut each bread slice in half diagonally. Broil 6-inches from heat until lightly toasted, about 1 to 2 minutes. Set aside.
Place mayonnaise, garlic salt, ginger, onions, celery, water chestnuts and eggs in blender or food processor container.
Blend at medium speed or process, scraping down sides occasionally, until vegetables are finely chopped and mixture is well blended. Stir in shrimp.
Spread shrimp mixture evenly onto reserved toast. Bake in preheated 425°F oven until warmed through, about 5 to 10 minutes. Garnish with additional shrimp, radish slices and green onion tops, if desired.