Prep the calamari: Rinse the squid rings and pat them very dry with paper towels. Drying helps the coating stick and crisp up.
Soak for tenderness: Place rings in the buttermilk (or milk-lemon mix) with 1/4 teaspoon salt.
Let sit 10–15 minutes while you prep the coatings.
Mix the crumb coating: In a shallow bowl, stir together panko, rainbow pepper, garlic powder, paprika, and 1 teaspoon salt. Taste a pinch of the mix; it should be well-seasoned and peppery.
Set up the dredging station: Put flour in one shallow bowl, beaten eggs in another, and the seasoned breadcrumbs in a third.
Dredge the rings: Working in batches, shake excess liquid from the squid, toss in flour, dip in egg, then coat thoroughly in breadcrumbs. Press gently so the crumbs adhere.
Preheat the air fryer: Heat to 400°F (200°C) for 3–5 minutes.
Lightly spray the basket with oil to prevent sticking.
Arrange and spray: Place coated rings in a single layer with space between each. Spray the tops lightly with olive oil for even browning.
Air-fry: Cook at 400°F (200°C) for 6–8 minutes, flipping halfway and spraying again if needed. They’re done when golden and crisp, and the squid is opaque and tender.
Avoid overcooking.
Make the tartar sauce: While the rings cook, mix mayo, pickles, capers, dill, lemon juice, and Dijon. Season with salt and pepper and adjust lemon to taste. Chill until serving.
Serve: Pile the hot calamari on a platter, squeeze with lemon, and serve with tartar sauce on the side.
Add extra rainbow pepper over the top for color and heat.