Pat scallops very dry with paper towels. Remove and discard the small side muscle if still attached so scallops lie flat. Season both sides lightly with kosher salt and freshly ground black pepper; set on a tray while you make the marinade and sauce.

Marinate briefly

In a small bowl whisk together chili garlic sauce, soy sauce, lime juice, and sesame oil. Place scallops in a shallow dish, spoon the marinade over them, turn to coat, and let sit at room temperature for 10–15 minutes (no longer than 20 minutes to avoid breaking down texture). Reserve any excess marinade for finishing sauce if desired.

Spicy Butter Sauce

Make the sauce

In a small saucepan or skillet over low heat, melt the unsalted butter. Add the minced garlic and ginger and cook gently for about 30–45 seconds until fragrant but not browned. Stir in red chili flakes, gochujang, honey, and rice vinegar. Cook, stirring, for 30–45 seconds to combine. If the sauce seems too thick, add 1 tablespoon water and stir. Keep warm on the lowest heat while scallops cook.

Cook & Finish

Sear scallops

Heat a large heavy skillet (preferably stainless steel or cast iron) over medium-high until very hot. Add 1 teaspoon neutral oil and swirl to coat. Remove scallops from the marinade, letting excess drip off (reserve marinade). Place scallops in the pan spaced at least 1/2 inch apart; do not crowd. Sear without moving for 1.75–2.5 minutes until a deep golden-brown crust forms. Flip scallops and sear the other side 1.25–2 minutes until just opaque in the center. Total cook time depends on size—do not overcook.

Combine with sauce

After flipping or as scallops finish, spoon the warm spicy butter sauce over the scallops and add a tablespoon of the reserved marinade if you like extra punch (ensure marinade is brought to a boil for 30 seconds if it's raw soy-based—alternatively add only unused marinade that has been heated). Tilt the pan and spoon the sauce 2–3 times so scallops become glazed.

Rest & garnish

Transfer scallops to a warm plate. Spoon any remaining sauce from the pan over them. Sprinkle with sliced green onion (white parts for immediate garnish, green parts on top), chopped cilantro, and toasted sesame seeds. Serve immediately with lime wedges to squeeze over just before eating.