Preheat oven to 350°F.
In small bowl, with fork, mix together tuna, parsley, lemon zest and juice, and black pepper. Set aside.
Remove whole peppers from jar and set aside 6 to be stuffed. In bowl of food processor, place remaining peppers with hazelnuts, olive oil, paprika, garlic, sherry vinegar, and 1 tsp honey, and pulse to blend into a sauce. The texture will not be completely smooth.
Add about 2 Tbsp of sauce to tuna mixture and stir through. Spoon remaining sauce into small baking dish to make a base for stuffed peppers.
Stuff tuna mixture into 6 piquillo peppers and place them on top of the sauce in baking dish. Drizzle with remaining 1 tsp honey and bake for 15 to 20 minutes.
Enjoy!