Preheat oven to 350 degrees.
Spray mini muffin tins with cooking oil spray. In a small bowl, mix together sesame oil and olive oil.
Stack 10 wonton wrappers. Place round cookie cutter on top of wonton wrapper stack. Use sharp knife to cut wonton wrappers into circles, using cookie cutter as a guide. Lightly brush each wrapper with sesame/olive oil mixture.
Place one wonton wrapper in each muffin tin. Use two fingers from each hand to gently press wrappers into bottom of muffin tins.
Bake for 5 minutes or until crispy and lightly browned.
Finely dice tuna. Place in medium bowl, along with mirin, sesame oil, soy sauce, 1 tablespoon scallions and sriracha sauce (start with 1 teaspoon and add more to your liking). Mix well; refrigerate until time to serve.
Spoon tuna tartare into wonton cups. Sprinkle with rest of scallions and toasted sesame seeds.