1. Remove the bones and cut the salmon fillet into 6 pieces at a 45-degree angle along the bias. Try to maintain uniform thickness in the slices, cutting wider pieces toward the narrower ends of the salmon and thinner pieces toward the thick center of the salmon.
2. Using a basting brush and about half of the butter rub, coat one side of the salmon pieces with the rub. Refrigerate the salmon for 5 minutes, or until the butter just hardens into a glaze.
3. Heat a large skillet or griddle over medium-high heat.
4. Lay the salmon pieces, butter-rub side down, in the pan and cook until the bottom half of the salmon flesh is opaque, about 3 minutes. Brush the remaining butter rub over the salmon and flip the pieces. Cook for 1 more minute. The salmon will be nearly opaque throughout but still very moist.
5. Serve hot, topped with blueberry sauce.