Preheat the air fryer. Set it to 390°F (200°C). This helps the salmon and veggies brown nicely.
Prep the veggies. In a bowl, toss potatoes, broccoli, red bell pepper, and onion with 1–2 tablespoons olive oil, half the lemon zest, half the garlic, oregano, 1/2 teaspoon paprika, salt, and pepper. Potatoes should be cut small so they cook through at the same time.
Start the veggies. Add the seasoned veggies to the air fryer basket in an even layer.
Cook for 8 minutes, shaking halfway. You want them starting to soften and color.
Season the salmon. Pat the fillets dry. Rub with 1 tablespoon olive oil, remaining lemon zest and garlic, 1/2 teaspoon paprika, salt, and pepper.
Squeeze a little lemon juice over the top.
Add salmon to the basket. After the first 8 minutes on the veggies, scoot them to the sides to make room. Place the salmon fillets skin-side down in the center. Avoid crowding; work in batches if needed.
Air fry until just done. Cook 7–10 minutes more, depending on fillet thickness.
The salmon should flake easily with a fork and read 125–130°F for medium. Veggies should be tender with caramelized edges.
Finish and serve. Squeeze more lemon over everything and sprinkle with chopped parsley or dill if you like. Add a pinch of red pepper flakes for heat or a spoon of Greek yogurt for creaminess.