Mayo-less tuna salad

I have really missed eating tuna these last 9 months.  The past week I have had it for lunch every single day.  I go through phases with my food where I become obsessed with something and eat it non-stop.  Tuna is clearly my current obsession.  Eating mayo everyday is kinda gross, so I came up with a healthier version of the traditional tuna salad!  It's pretty darn good if I do say so myself!  

Ingredients: 

1 can tuna 

1/2 ripe avocado

1/4 cup plain greek yogurt

1/4 tsp garlic salt

1/4 tsp pepper 

Optional Ingredients:

red onion

celery

green apple