Heat extra virgin olive oil in a skillet over medium heat. Cook and stir onion, red pepper, celery, and a pinch of salt in hot oil until onion is soft and translucent, about 5 minutes. Add capers; cook and stir until fragrant, about 2 minutes. Remove from heat and cool to room temperature.
Stir salmon, onion mixture, mayonnaise, 1/4 cup bread crumbs, garlic, mustard, cayenne, seafood seasoning, salt, and ground black pepper together in a bowl until well-mixed. Cover the bowl with plastic wrap and refrigerate until firmed and chilled, 1 to 2 hours.
Form salmon mixture into four 1-inch thick patties; sprinkle remaining panko bread crumbs over each patty.
Heat olive oil in a skillet over medium-heat. Cook patties in hot oil until golden and cooked through, 3 to 4 minutes per side.