Place habaneros, garlic with skin and onion on pan and heat until burned. Remove when they are completely black.
Blend with 1 cup of vegetable oil salt and black pepper to taste.
For the Tostada:
Cut the tuna sashimi style. Combine the tuna with the habanero sauce.
Thinly slice the radish in quarters. Place a thin layer of watermelon atop each tostada, followed by tuna mixture. Then top with cucumber, radish and onion. Pipe out of avocado mousse around the tostada.
Season to taste.
Finish with a generous drizzle of extra virgin olive oil and rice caviar and serve right away.