Combine the pork, grated onion, fennel seeds, bread crumbs, egg and parsley, in a large mixing bowl. Season the ingredients well with the sea salt and black pepper. Then use your hands, to mix everything thoroughly. Shape the meat into four patties, cover and leave them in the refrigerator for 30 minutes.
Heat a frying pan or grill pan over high heat. Add the burgers, and cook until the burgers are browned and cooked through, about 4 to 5 minutes on each side.
Set the patties on the hamburger buns and layer them with arugula leaves, roasted peppers /chiles, and a few slices of the red onion. Serve with sweet potato fries.
Preheat the oven to 450 degrees F.
Toss the sweet potato batons with the olive oil, paprika, cayenne pepper, and some sea salt. Scatter then in a single layer on a large baking tray and bake for 30 minutes, stirring occasionally, until the fries are golden brown. Serve with lime wedges.