Cook 12 oz. linguine in a large pot of boiling salted water, stirring occasionally, until al dente. Drain, reserving 1 cup pasta cooking liquid.

Meanwhile, heat 2 Tbsp. extra-virgin olive oil in a large skillet over medium-high. Add ½ cup panko, season with kosher salt, and cook, stirring often, until golden brown and crisp, about 3 minutes. Transfer to a small bowl. Wipe out skillet.

Heat 2 Tbsp. extra-virgin olive oil in same skillet over medium-high. Add two 4.2-oz. cans octopus, drained, patted dry, and cook, tossing occasionally, until golden brown and crisp, 2–3 minutes. Using a slotted spoon, transfer to a plate.

Add remaining 1 Tbsp. extra-virgin olive oil to same skillet. Cook 5 garlic cloves, coarsely chopped, and 3 Tbsp. coarsely chopped drained capers, stirring often, until slightly softened, about 2 minutes. Add ¼ tsp. crushed red pepper flakes and a big pinch of salt; season generously with freshly ground black pepper. Cook, stirring constantly, until combined and fragrant, about 1 minute. Add 1 cup dry white wine and cook, stirring often, until reduced by two thirds, about 4 minutes.

Add pasta, ½ cup (packed) finely chopped parsley, 4 Tbsp. unsalted butter, and reserved ½ cup pasta cooking liquid to skillet; reduce heat to medium-low. Cook, tossing often and adding remaining pasta cooking liquid a little at a time as needed, until pasta is coated. Remove from heat. Add octopus, then finely grate zest from 1 lemon over. Cut lemon in half. Squeeze in juice from 1 half and toss to combine. Cut remaining half into wedges.

Divide pasta among shallow bowls and top with panko mixture. Serve with lemon wedges for squeezing over.