Preheat the oven to 400°.
Roughly peel two russet potatoes and quarter them. Place them in a pot of water and boil on medium-high for 15 minutes until fork-tender. While the potatoes boil, prep the jalapeño pepper, mince the garlic, and cut the onions into fine dice.
When the potatoes are finished boiling, strain off the water and smash with a fork. Set aside. You'll need one cup of mashed potatoes.
Line a walled cooking sheet with aluminum foil. Brush the salmon with two tablespoons of olive oil, then season with sea salt or Kosher salt and freshly cracked black peppercorns. If you have fresh herbs like thyme, rosemary, or tarragon, lay them on the center of the baking sheet and place the salmon on top of the herbs.
Place the salmon on the center rack of the preheated 400° oven and bake for 30-35 minutes.
The finished salmon should be firm to the touch, have an internal temperature of an instant-read thermometer of 145°, and flake with the tines of a fork.
While the salmon is cooling, place a small skillet over medium heat and add a tablespoon of olive oil and unsalted butter. Peel and finely dice a small onion, measuring 1/4 cup. Chop the garlic as well.
When the oil is hot, sauté the onion and garlic, moving the mixture around to prevent them from burning. Sauté until the onions begin to soften, about three (3) minutes. Turn off the stovetop, spoon the onion and garlic mixture into a bowl, and set aside.
When the salmon is cool enough to handle safely, flake 2 cups into a large mixing bowl. Add the mashed potatoes, 1/2 cup of the panko breadcrumbs, egg, and mayo. Also, add the sautéed diced onion, jalapeño pepper, garlic, chopped dill, Old Bay Hot seasoning, sea salt, and freshly cracked black peppercorns, then mix well. Add the remaining panko breadcrumbs and continue mixing.
Spoon about 1/4 cup of the salmon and potato mixture into your palm, about the size of a golf ball, form it into a ball, and press it gently into a patty.
Place on a cooking sheet lined with parchment or wax paper.
Chill the croquettes in the fridge for 1-2 hours or overnight if making ahead.
Place a large skillet over med-high heat and add the cooking oil (Heat the oil to about 350°F if using a thermometer).
Add three or four salmon croquettes when the oil is hot and cook until the bottoms are golden brown, about 4-5 minutes per side.
Using a spatula, turn the croquettes over and cook until the opposite side is golden brown, too.
Place the finished salmon croquettes onto a plate lined with parchment paper or paper towels.
Serve with the cucumber aioli (recipe below), a fresh garden salad, and a bottle of chilled Stella Artois® Solstice Lager.