Make the chile crunch: Combine Special K, garlic, shallots, gochugaru, sesame seeds, dashi granules, Taíin, coriander, and cayenne (if using) in a medium heatproof bowl. Heat the oil in a small saucepan over medium until it registers 350°F on an instant-read thermometer, about 5 minutes. Very carefully pour the hot oil over the dry ingredients, stir gently, and let the chile crunch stand until ready to use.

Make the salad: Combine the onion and jalapeño in another medium heatproof bowl. Bring the vinegar just to a boil in a small saucepan over high. Pour the vinegar over the onion and jalapeño; mix well.

Cut the cucumbers in half crosswise. Using the side of a knife or a rolling pin, smash the cucumbers and then tear them into large chunks; discard any seeds that separate from the cucumbers. Add the cucumbers to the onion and jalapeño mixture; toss well. Let stand for 5 minutes, then pour off the liquid. Add the cilantro, mint, and 1 tablespoon of the chile crunch; toss well.

Make the salmon: Season the salmon with salt and pepper. Heat the oil in a large skillet over medium-high until shimmering. Add the salmon, skin side down, and cook, pressing gently with a spatula to flatten, until the skin is browned and crisp, about 3 minutes. Flip the salmon and cook until an instant-read thermometer inserted into the thickest portion registers 130°F for medium, about 3 minutes more. Transfer the salmon to a plate.

To serve, spoon the evenly divided Greek yogurt onto 4 plates. Spoon the cucumber salad over the yogurt and place the salmon fillets on top. Spoon some of the chile crunch over top and garnish with torn mint and cilantro leaves. Serve immediately with additional chile crunch on the side.