• Preheat the oven to 350 degrees Fahrenheit.

For the pickles:

• Thinly slice the cucumber into ⅛-inch thick slices and transfer to a medium-sized bowl.
• In a small saucepan, combine the water, vinegar, sugar, and kosher salt. Stir the mixture over medium heat until the sugar is dissolved and the mixture is hot.
• Pour over the cucumbers and set aside.

For the mahi mahi:

• In a small bowl, combine the paprika, onion powder, garlic powder, black pepper, sugar, salt, oregano, and cayenne powder.
• Evenly coat the top of the mahi mahi fillets with the blackening seasoning. You may not need it all depending on the size of your fillets.
• Heat a large nonstick skillet over medium-high heat. Add one teaspoon of olive oil to the skillet. Place the buns, sliced side down, into the skillet. Cook the buns until lightly golden brown. Set the buns aside.
• In the same skillet, add one tablespoon of olive oil. Place the mahi mahi fillets in the skillet, seasoned side down. Let them cook for 2 minutes undisturbed.
• Carefully flip the fillets over and place the skillet in the oven. Bake until the fillets are opaque and flake easily, about 6 to 8 minutes.
• Use an oven mitt to carefully remove the skillet from the oven. Transfer the fillets to a plate so they don't overcook.

For the aioli:

• As the mahi mahi bakes, make the aioli. In a small bowl, combine the mayo, garlic, dill, lemon juice, lemon zest, sugar, and salt. Stir to combine.

Assemble:

• Drain the liquid from the pickles.
• Divide the shredded lettuce between the two bottom buns. Top the lettuce with the blackened mahi mahi fillets.
• Slather the lemon aioli on the cut side of the top buns. Cover the aioli with a layer of pickles.
• Place the top bun onto the mahi mahi to create a sandwich. Enjoy immediately!