Bring 1cup water and 1 cup vinegar to a boil. Add onions to a mason jar and pour hot brine over the top. Let sit for at least 15 minutes for them to quick pickle.
Meanwhile, fill a sauce pot with 5 cups water. Bring it to a boil, add 1 tablespoon vinegar and slides eggs in with a spoon. Lower heat to barely a simmer and cook for 4 minutes for runny yolks, 5 minutes for thicker yolks. Remove from heat with slotted spoon and pat dry.
Blend avocado, sour cream, lime juice, salt, and garlic to a food processor and blend until creamy. Add a little water if you would like it a little thinner in consistency.
Then build your benedict, open face on the english muffins. A few slices of smoked salmon, shaved cucumber, poached eggs, pickled onion and then a hefty drizzle of avocado sauce.