Skin and debone the salmon, then chop it fine by hand (food processor makes it gluey).
In a medium bowl, combine salmon, herbs, coriander seed, and ginger. Stir well, then season with salt and pepper.
Spread panko bread crumbs in a shallow bowl or pie plate, and arrange a piece of parchment paper on a baking sheet. Divide salmon mixture into 4 even portions and, working one at a time, roll each into a ball, then flatten into a 1-inch thick patty, using your hands to smooth out any cracked edges (they may squirm around on you a little, but keep at it and they'll come together).
Place each patty in the bowl of bread crumbs, use your hands to sprinkle more bread crumbs on top, then press down gently to make bread crumbs adhere to the bottom side. Flip patty and press gently once more, then transfer to the parchment-lined baking sheet. Repeat with remaining salmon.
Add oil to a large cast iron skillet and heat over medium-high heat until shimmering. Carefully lower salmon patties into the oil and cook, turning once or twice, until lightly browned on both sides and medium-rare within (about 115 to 120°F on an instant-read thermometer), about 10 minutes; adjust heat as necessary to keep things sizzling without scorching the bread crumbs.
Transfer patties to a paper towel-lined tray and sprinkle lightly with kosher salt. Assemble your burgers (we recommend tartar sauce and coleslaw toppings) and enjoy.
