Preheat the oven to 400 degrees. Wash the sweet potatoes and poke a few holes with a fork on each side.
Grease the part of the baking sheet with some coconut oil where you are going to put the sweet potatoes. Place the sweet potatoes on there and bake for about 30-40 minutes or until fork-tender. Baking time will vary depending on the size of the sweet potatoes and how soft you prefer them.
After half of the cooking time start preparing the stuffing. If the tuna you are using is packed in olive oil, pour most of it in a jar and save it for your next tuna salad. If it is packed in water discard the water.
In a medium bowl mix together coconut yogurt, tuna, and the juice of half a lemon. Stir until smooth.
Finely mince onion and chop apples into small pieces. Add them to the tuna mix and stir. Depending on how many apple pieces you would like in your dip, either add 1/4 or 1/2 an apple. Season with salt and pepper to your liking.
Once the sweet potatoes are done slice them open and season the inside with salt and pepper. Stuff the inside with the tuna dip. Add chopped parsley or cilantro as a garnish and enjoy.