Using a sharp knife, halve shrimp lengthwise leaving the tail in-tact, so that halves are still attached at the tail; set aside. In a medium bowl, whisk together black bean sauce, hoisin sauce, soy sauce, and squid ink; set aside.
Heat 2 tablespoons oil in a large skillet or wok over medium-high heat. Add half the shrimp to skillet and cook, stirring, until opaque, 3 to 5 minutes. Add half the black bean sauce mixture and stir to combine. Transfer shrimp to a plate and wipe skillet clean. Repeat process with remaining 2 tablespoons oil, shrimp, and black bean sauce mixture.
To serve, place each shrimp on a small plate or serving spoon and sprinkle with a pinch of sesame seeds.