Heat oven to 375 degrees.
Cut each pita into eight wedges.
Brush lightly with olive oil and sprinkle with coarse sea salt.
Spread in a single layer on a cookie sheet and bake for 10-15 minutes, flipping once.
Let cool.
In a medium bowl, combine tomato, basil, onions, garlic, olive oil and vinegar.
Sprinkle with salt and pepper.
Refrigerate tomato mixture for at least 20 minutes to blend flavors.
In a small bowl, combine tuna with Italian seasoning and salt and pepper to taste.
To serve, place a spoonful of tuna on each pita wedge. Top with tomato mixture.