Mix 1/4 cup soy sauce, green onions, 3 tablespoons sugar, oil, garlic, sesame oil, and 1 teaspoon sesame seeds together in a bowl. Add beef to the marinade. Let sit until flavors are well absorbed, at least 30 minutes.
Mix 6 tablespoons soy sauce, vinegar, 2 teaspoons sesame seeds, ginger root, paprika, cayenne pepper, and 1 pinch sugar together in a separate bowl to make the dipping sauce.
Heat a skillet over medium-high heat. Cook and stir beef until firm and lightly browned, 8 to 10 minutes. Serve with dipping sauce.