Heat 1 tsp vegetable oil in non-stick saucepan over med heat. Cook 1 finely chopped shallot and 2 cloves finely chopped garlic gently until fragrant, but not brown. Stir in 1 tbsp black bean sauce, 1/2 cup mirin (Japanese sweet wine), and 1 tbsp soy sauce. Bring to boil and cook until reduced by half. Remove from heat, and stir in 1 tbsp rice vinegar; set aside. Pat Halibut filets dry. Rub with 1 tsp sesame oil and sprinkle with pepper. Preheat an outdoor grill for high heat, and lightly oil grate. Grill fish for about 5 minutes per side, or just until cooked through. Sprinkle with cilantro. Serve with sauce poured over top.