Whisk the eggs, 1 tablespoon paprika, 1 teaspoon cayenne and 4 teaspoons salt in a large glass bowl. Add the milk, parsley, sage and garlic.
Slice the onions into 1/8-inch-thick rings with a mandoline or knife. Separate the rings and add to the milk mixture. Add the chicken, turning to distribute the ingredients. Cover and refrigerate for 4 to 8 hours.
In a shallow baking dish, mix the flour, the remaining 1 tablespoon paprika and 1/2 teaspoon cayenne, 2 teaspoons salt and 1 teaspoon black pepper. Place a rack on a baking sheet. Lift each piece of chicken from the milk mixture, roll in the flour mixture and place on the rack. Once all the pieces are floured, re-dip in the milk mixture and press some of the onions and herbs onto the chicken. Then, pressing the onions onto the chicken to hold them in place, roll the chicken in the flour again, pressing firmly so the onions become part of the breading. (You can re-dip a third time to add more onion, if you like.) Set the onion-coated chicken pieces on the rack.
Heat about 3/4 inch of vegetable oil in a deep-fryer or large deep skillet over medium-high heat until a deep-fry thermometer registers 375 degrees. Add the chicken and fry, adjusting the heat as needed, until golden brown on one side, 8 to 10 minutes. Turn with tongs and cook until the chicken is golden all over and a thermometer inserted into the thickest part registers 160 degrees, about 8 more minutes. Drain on a paper-towel-lined plate. Season with salt.