In a medium bowl, combine the red wine vinegar, salt, sugar, hot sauce and 1 cup of cold water. Add the onions and the radishes to the vinegar mixture and reserve.
Clean the crabs by flipping up each side and removing the lungs. Pull the "apron" flap off of the bottom of the crab. Using a sharp pair of scissors cut the face off the crab, this seems really mean - it is- accept it and move on.
Soft-shell crabs usually have a lot of water in them which can be very dangerous during frying. Pat the crabs with paper towels to remove excess water.
Add the frying oil to a large saute pan until it reaches a depth of 1/4-inch. Bring to a medium-high heat.
While the oil is heating, in a large bowl, toss together the mesclun, zucchini, some of the pickled onions and radishes with some of the pickling liquid, and a drizzle of extra-virgin olive oil. The salad should be lightly dressed, very flavorful and not soggy. Arrange the salad on 4 individual salad plates.
Set up a plate lined with paper towels to drain the crabs when they come out of the frying pan. Check the temperature of the oil by flicking flour into the pan. The flour will sizzle when the oil is hot. Put the flour into a shallow dish. When the oil is hot dredge the crabs the flour and pat off the excess. Gently add the crabs to the pan. When putting the crabs in the pan, be careful not to throw them in the oil because the hot oil will splash. Fry the crabs until crispy on both sides, about 3 to 4 minutes. Remove them from the pan to paper towels to blot excess oil. Sprinkle with salt and put 1 crab on each of the prepared salads. Garnish with a dollop of the garlic aioli and serve.
In the bowl of a food processor, add the garlic, vinegar and egg yolks. Turn the machine on. While the machine is running begin adding the oil, drop by drop, until you see the mixture thicken. When the mixture begins to look like a smooth homogeneous mixture, the oil can be added in a slow thin stream. If the mixture is too thick, add a few drops of water to thin it down. Season with salt and taste to make sure it is delicious.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.