Making the gravlax: Lay the salmon, skin-side down, on a clean, dry surface. Pack the dry rub evenly over the fillets and wrap each piece tightly in two layers of plastic wrap. Place one piece of the fish, skin-side down, in a pan large enough to accommodate it. Place the other piece, skin-side up, on top of the first. Lay a cutting board on top of the fish, and weigh down the board with tomato cans. Refrigerate for 24 hours. Unwrap the fish and drain the liquid. Re-wrap the fish tightly and reverse the position of the fillets. Return to the refrigerator, chill for another 24 hours and repeat the process again. Remove the salmon from the plastic wrap and brush off the spices and salt. Very thinly slice the salmon on the bias using an extremely sharp knife.
Toast the pumpernickel and rub each slice with garlic. Combine the mustard and honey, then spread onto the toast and garnish with several slices of pastrami gravlax. Finish with baby arugula and/or slices of garlic dill pickles.