Dilute vinegar with 2 tablespoons of water and toss with cabbage. salt and pepper to taste. Cover and chill.
Remove husks from and rinse tomatillos. Brush tomatillos, onions and chiles with oil. Place them over hot coals about 4 to 6 inches from heat source. Grill, turning as needed, until vegetables just begin to blacken, about 8 to 10 minutes. Remove from grill and set aside to cool. The vegetables can also be roasted under the broiler for 4 to 5 minutes per side.
Brush fish with remaining oil and place over medium hot coals. Grill about 5 to 7 minutes per side, turning once, until fish is opaque at the thickest part. Since charcoal grill temperatures differ greatly, test your fish with a fork to make sure it is cooked. If it flakes easily, it is usually ready to remove from the grill.
Meanwhile, remove stems from chiles. In a blender, process tomatillos, chiles, lime juice, cilantro and garlic until smooth. Chop onion and stir into salsa mixture. Pour into a small serving bowl. Add salt to taste.
Remove fish from grill. Assemble tacos by placing cabbage in flour tortilla, add several chunks of grilled fish, green salsa, jack cheese and top with sour cream. Add a squeeze of lime and enjoy!This recipe also works wonders on boneless chicken breasts or thighs.