Drain the tuna and add to a food processor. Add in the rest of the ingredients to the food processor and blend until well combined. Add more mayonnaise if need be. Taste and add more sriracha if you prefer it spicier!
Optional: Toast your bread slices and let it cool before assembling your sandwich.
Evenly spread about 1/4 of the tuna salad on one piece of bread. Layer on top of the tuna the veggies of your choice (one, some, or all of my suggested toppings!).
Slice in half with a large, sharp knife and enjoy!