Cut beef roast into 2 to 3" pieces; season with pepper. Coat large nonstick skillet with nonstick spray; heat over medium until hot. Add half of beef; brown evenly, 3 to 4 minutes per side.
Transfer beef to slow cooker. Repeat with remaining beef.
Add stock to skillet; cook and stir 1 to 2 minutes or until browned bits attached to skillet are dissolved. Stir in gochujang, garlic, fish sauce, hoisin sauce and sambal. Pour mixture into slow cooker. Cover and cook on HIGH 4 hours or LOW 6 hours or until roast is fork-tender.
Meanwhile, combine cucumber, carrots, ginger and vinegar in small bowl. Cover and refrigerate.
Remove roast from slow cooker. Skim fat from cooking liquid. Reserve 1 tablespoon cooking liquid. Shred beef with 2 forks. Combine shredded beef, remaining cooking liquid and lime juice. Season with salt and pepper, as desired. Cover; keep warm.
Combine Beef Chopped Liver, reserved 1 tablespoon cooking liquid, plum sauce and Cognac in small bowl; mix well. Season with salt, as desired. Using a whisk, whip cream in small deep bowl to soft peaks. Fold cream into liver mixture. Cover and refrigerate until ready to serve.
Spread 2 teaspoons liver mixture evenly over cut sides of each roll. Divide shredded beef evenly among rolls; top with cucumber mixture. Top with additional pickled onions, radishes, carrot, basil, mint, jalapeño peppers, cilantro and lime wedges, if desired.
Nutrition information per serving: 582 Calories; 207 kcal Calories from fat; 23 g Total Fat; 9 g Saturated Fat; 10 g Monounsaturated Fat; 173 mg Cholesterol; 1148 mg Sodium; 37 g Total Carbohydrate; 3.8 g Dietary Fiber; 51 g Protein; 6.9 mg Iron; 6.7 mg NE Niacin; 0.6 mg Vitamin B6; 6.7 mcg Vitamin B12; 15.3 mg Zinc; 52.3 mcg Selenium; 199.3 mg Choline;