Cut your onion into a small dice
Cut the avocado in half lengthways. Use a teaspoon to hallow out the center of 1/2 the avocado slightly, to give you more space for filling. Grind some black pepper over the half you are using, use a dash of the lime juice to save the other half.
Drain the tuna and add to a mixing bowl, along with the extra avocado, cream cheese, yogurt, onion, PERi-PERi sauce, lime juice and a sprinkle of salt and pepper to taste. Mix well.
Pile tune high into your avocado half.
Drizzle with more PERi-PERi to taste and enjoy!