Preheat your grill to medium-high heat and oil the grates well to prevent sticking. While the grill heats, combine the olive oil, minced garlic, smoked paprika, salt, black pepper, and red pepper flakes in a small bowl. Stir until the spices are evenly distributed throughout the oil—this creates an aromatic coating that will develop flavor on the shrimp.
Pat the shrimp dry with paper towels, then toss them with the oil and spice mixture from Step 1 until evenly coated. Place the shrimp directly on the hot grill grates in a single layer. Grill for 1-3 minutes per side until they turn opaque and develop light char marks—I find shrimp cooks quickly, so watch carefully to avoid overcooking, which makes them tough and rubbery. The shrimp should be just cooked through when the flesh turns from translucent to fully opaque.
Transfer the grilled shrimp to a serving platter. Drizzle or toss the shrimp with the bang bang sauce, coating them generously. Finish with a squeeze of fresh lime juice to brighten the rich sauce, then scatter the thinly sliced scallions over the top for a fresh, crisp garnish. I like to reserve a bit of the sauce on the side for dipping, since the citrus and spice combination is addictive.