Combine the crushed chips with the flour, 1/2 teaspoon salt and the cayenne pepper in a shallow bowl. Whisk the eggs, tartar sauce and 3 tablespoons water in another shallow bowl. One at a time, dredge each fish strip in the potato chip mixture, turning to coat, then dip in the egg mixture and dredge again in the potato chip mixture. Place on a baking sheet until ready to fry. Fill a large skillet about halfway with vegetable oil and heat over medium-high heat until a deep-fry thermometer registers 350 degrees F. Working in batches, fry the fish, turning, until golden brown and crisp, 5 to 8 minutes. (Let the oil return to 350 degrees F between batches.) Drain on paper towels and season with salt. Serve with lemon wedges and/or vinegar.