In a large skillet, heat olive oil over medium-high heat.
Add ground beef and cook until browned, breaking it apart with a spatula, about 5-7 minutes.
Stir in soy sauce, sesame oil, gochujang, minced garlic, grated ginger, erythritol, and rice vinegar. Cook for an additional 3-5 minutes until the beef is well coated and heated through. Season with salt and pepper to taste.
While the beef is cooking, prepare the cucumber salad. In a bowl, combine sliced cucumber, sesame seeds, and chopped green onions. Toss gently to mix.
Serve the spicy beef hot, garnished with additional green onions if desired, alongside the cucumber salad.