Set oven to 400F.
Wash red potatoes and poke a few holes in them using a fork. Place them on a baking tray and bake for 45 minutes – 55 minutes, or until you can easily pierce them with a toothpick. Remove the potatoes from the tray after baking and allow them to cool, enough to be handled by hand.
Carefully skim off the top of the cooked red potato. Using a spoon, carve out the inside of the potato to create a hollow ball. Place the scooped out flesh and top in a large bowl. Repeat.
Mash up the red potato using a masher or fork. Try to get as many of the lumps out as possible. Then, add Greek yogurt, mustard, garlic, chives and dill. Mix and mash everything together until smooth.
Add the cheese and tuna, then mix and mash again. Add olive oil and season to taste with sea salt & pepper, mix and mash using a spatula until smooth, or you reach your desired consistency.
Fill the hollowed out red potatoes with the filling. Add a pinch of pepper (and cheese) on top if desired. Bake in the oven for 15 to 20 minutes, or until the outside is golden brown. TIP: spray the potatoes with a little olive oil before baking.
While the potatoes are baking, spray a nonstick skillet with olive oil and place on medium-high heat. Once the skillet is warm, add the asparagus spears and minced garlic. Move the asparagus around in the skillet so it is seared on all sides. While it is searing, squeeze in some lemon juice to create steam and caramelize the spears. Sear for 3 to 5 minutes then remove from the skillet.
Enjoy the stuffed potatoes with grilled asparagus.