To prepare aioli, combine cilantro, mayonnaise, serrano, and minced garlic, stirring well.
To prepare fish, combine milk and egg white in a shallow dish, stirring well with a whisk. Combine cornflakes, flour, salt, and black pepper in another shallow dish.
Heat 2 tablespoons olive oil in a large nonstick skillet over medium-high heat. Dip fish in milk mixture, and dredge in cornflake mixture. Add fish to pan, and cook 4 minutes on each side or until fish flakes easily when tested with a fork or until desired degree of doneness. Serve fish with aioli and lemon wedges.