Boil shrimp in 5 cups water in a medium saucepan 3 to 5 minutes or just until shrimp turn pink. Drain and rinse with cold water.
Peel shrimp, and devein, if desired. Chop shrimp.
Stir together shrimp, crabmeat, and next 8 ingredients; cover and chill up to 24 hours. Serve on cucumber slices and squash slices or in phyllo cups. Garnish, if desired.