To make the marinade, combine soy sauce, sugar, sesame oil, garlic, ginger, and sesame seeds in a large bowl. Add the thinly sliced beef, turning to coat, cover, and refrigerate for 30 minutes.
In a small bowl, combine gochujang, doenjang, rice vinegar, soy sauce, and sesame oil. Cover and refrigerate until needed.
Place a large wok or pan over high heat. Once heated, add the beef with the marinade. Cook, stirring constantly, until browned, 2-4 minutes. Remove from heat.
Use lettuce leaves to wrap beef with the rice and ssamjang. Serve with kimchi.