Stir together caviar and wasabi paste; set aside.
Combine mango and mayonnaise in a blender, and process until smooth. Stir in caviar mixture.
Combine tuna and next 7 ingredients in a large bowl; toss gently.
Spoon about 1 tablespoon mango mayonnaise into each of 8 martini glasses. Top each evenly with tuna mixture; spoon additional mango mayonnaise over each. Garnish, if desired.
Note: If you are able to purchase wasabi tobiko, use a 2-ounce jar in place of golden caviar and wasabi paste.