Combine vinegar and sugar in small saucepan, boil for 1 minute. Put sliced onion in bowl and pour vinegar mixture over onions; chill until ready to serve. Using blender, puree avocados, sour cream and1/2 lime juice. Scoop into small bowl. In another bowl mix coleslaw, remaining lime juice (a little oil if you wish)and pinch of salt. Season shrimp w/taco seasoning and sautee 2-3 minutes to warm. Serve shrimp in warm tortillas adding avocado sauce, onion mixture and coleslaw as desired.
