Place flounder fillets in a small glass dish. Mix lemon juice, garlic, cumin, and paprika in a small bowl; pour over flounder fillets. Cover dish with plastic wrap and marinate flounder in refrigerator for 2 hours.

Mix flour, dill weed, and cayenne pepper together on a piece of waxed paper.

Beat egg and water together in a wide bowl.

Heat oil in a large skillet over medium heat.

Gently press the flounder fillets into the flour mixture to coat; shake to remove excess flour. Dip into the beaten egg to coat and immediately return to the flour mixture to coat.

Fry flounder in hot oil until the fish flakes easily with a fork, about 5 minutes per side.