Preheat oven to 350F. Cut the stems and fronds off the fennel (reserve the greens!) and discard any bruised outer layers. Cut the fennel bulb in half lengthwise, then using a paring knife cut out the tough part of the core (you essentially cut a small triangle shape to remove). Thinly slice fennel (a mandoline is great, but I use a knife) and place in ice water while you prep the remaining ingredients.
In a small, shallow container or bowl, combine all-purpose flour with 1 Tbsp salt and 1 tsp freshly ground black pepper. Whisk eggs in a medium bowl to combine. Combine panko, parmesan cheese, sage, and remaining 1 Tbsp salt in a separate dish.
Heat a few tablespoons of olive or vegetable oil over medium-high heat in a large skillet. The amount of oil will depend on the size of the pan you use -- you need an even layer on the bottom of the pan that goes up approximately ⅛" - ¼" up the side. Dredge each cutlet in flour on both sides. Move chicken to the eggs, turning to coat on all sides, then shake off any excess. Finally, evenly coat cutlets on all sides in panko breadcrumbs. When oil is hot, transfer chicken and cook for 3-4 minutes per side, until golden brown, but not burned. Flip and cook another 3 minutes.
Move pan to the oven and bake for 6-8 minutes, or until chicken is fully cooked through. Chicken is safe to eat at 165F, but you can remove it from the oven when it’s reached ~155F — it will continue to cook while it rests. (If you’re making a larger portion, move chicken cutlets directly from the skillet to a baking sheet with a cooling rack on top. The chicken will stay crisp as long as it’s not directly on the baking sheet and air can circulate beneath).
While chicken is resting, toss salad greens with 1 Tbsp high quality olive oil in a medium bowl to coat; season with additional salt and pepper to taste.
Drain the fennel and pat dry on a paper towel to remove any excess water. Toss with 1-2 Tbsp olive oil and toss to coat.
Season chicken with a squeeze of fresh lemon juice, then sprinkle each cutlet with a pinch of flaky sea salt. Mound salad atop chicken, then top with plenty of sliced fennel. Garnish with reserved fennel fronds.