Set out three shallow dishes. In one add the flour and lightly season with a pinch of salt and pepper. You can also add an all-purpose seasoning here as well. Or add a bit of granulated garlic or onion if desired. In the second dish, whisk the eggs. In the third dish, add the panko bread crumbs and season lightly with a pinch of salt and pepper.
Cut the halloumi into 1/2-inch slices. You should get about 5 slices per package. To dredge, run each slice of cheese first into the flour, dusting off the excess, and then dip into the egg and then lastly into the breadcrumbs. Press each slice to evenly coat and then place on a wire rack that has been set over a baking sheet. Continue coating the rest of the cheese and set aside.
Fill a frying pan with about 2 inches of oil and set over moderate heat.
While the oil heats up, you can make the tartar sauce. In a small bowl, stir together the mayo, chopped pickles, scallions, lemon juice, capers, dill, mustard, hot sauce and a pinch of salt and pepper until evenly combined. Cover and chill until ready to use. The tartar sauce can be made in advance and kept in the fridge for up to a week.
Once the oil is hot, carefully add the coated cheese, a few at a time, and fry until golden brown and crispy on both sides, about 2-3 minutes per side. Drain and return to the wire rack. Continue frying the remaining cheese.
To assemble the sandwiches, toast the buns and spread both halves with the homemade tartar. Top the bottom bun with shredded lettuce, two slices of crispy halloumi and pickles. Place the top bun on and serve immediately. Enjoy!