Preheat the oven to 400 degrees F.
For the salmon: Season the salmon filets with salt and pepper. In a bowl, mix together the panko, parsley, dill, garlic and 1 tablespoon of the oil until the panko is evenly coated. Coat the salmon with the panko mixture and let sit for a few minutes so the crust
Heat the remaining 2 tablespoons of oil in an ovenproof skillet over medium-high heat. Add the salmon and cook until the breadcrumbs are golden, 2 to 3 minutes per side. Transfer the skillet to the oven and cook for 5 minutes. Keep the salmon warm.
For the salmon hash: Heat the oil in a large skillet over medium heat. Add the potatoes
and cook, stirring occasionally, until they start to brown, 4 to 5 minutes. Add the onion and bell pepper and cook until the potatoes are cooked through and the peppers are soft, 10 minutes more. Turn off the heat and stir in the salmon and capers
. Season with salt and pepper. Keep the hash warm.
To make the salad: Toss the bread cubes with 1 tablespoon of the oil on a baking sheet. Spread the bread in a single layer and toast in the oven, stirring once or twice, until crunchy but not too hard, 8 to 10 minutes.
In a large bowl, whisk together the vinegar, mustard, shallot, remaining 2 tablespoons oil, salt and pepper. Add the cucumber, tomatoes, onion
and stir to coat everything in the dressing
. Stir in the toasted bread.
For the sauce
: Heat the oil in a small skillet over low heat. Add the shallot and cook until softened, about 2 minutes. Turn off the heat and whisk
in the butter 1 piece at a time. Stir in the capers and dill. Squeeze in the lemon juice
and season with salt and pepper.
To plate: Divide the salmon hash among 4 plates and top each with a salmon filet
. Spoon the sauce over the salmon. Divide the salad among the plates, placing it on the side of the salmon.