1. Combine first 5 ingredients in a small bowl, stirring with a whisk. Cover and chill.
2. Preheat oven to 425°.
3. Coat a baking sheet with cooking spray, and spread evenly with oil; heat in oven 12 minutes.
4. Combine flour and black pepper in a shallow dish. Combine 1/2 cup beer, mustard blend, lime juice, egg whites, and egg in a shallow dish; stir with a whisk until foamy. Place panko, pumpkinseeds, cumin, and chipotle pepper in a food processor; pulse 20 times or until coarse crumbs form. Place panko mixture in a shallow dish.
5. Sprinkle fish evenly with salt. Working with one piece at a time, dredge fish in flour mixture. Dip in egg mixture, and dredge in panko mixture until completely covered.
6. Remove preheated baking sheet from oven; place fish on pan, and return to oven. Bake at 425° for 15 minutes or until fish flakes easily with fork, turning once. Serve immediately with sauce and lime wedges.
Sustainable Choice: If Pacific halibut is not available, you can use Alaskan pollack and U.S. Pacific cod as alternatives.