Dice the tuna into a fine squared dice
¼ lb Tuna
In a bowl mix together the mayo, sriracha, tamari and sesame oil and whisk together until well combined
3 Tablespoons Japanese Mayo, 1 Tablespoon Sriracha, 1 teaspoon Sesame oil, 1 teaspoon Tamari
Add the diced tuna to the bowl and set aside on the fridge while preparing the rest of the recipe.
In a bowl add the avocado, lime and Serrano pepper. Lightly mash them with a fork, leaving some chunks of avocado. Add salt and cilantro to taste.
½ Avocado, 1 Lime, ½ Tablespoon Serrano pepper, ½ Tablespoon Cilantro
Add the avocado mash to the tostada, top with the tuna and garnish with pickled onions
2 Tostadas, Pickled onions