In a medium bowl, combine thinly sliced cucumbers and red onions. Drizzle with apple cider vinegar, then sprinkle with sugar-free sweetener, salt, and black pepper. Toss until evenly coated and let sit for at least 10 minutes.

Heat a large skillet over medium-high heat. Add ground beef, breaking it apart with a spatula, and cook undisturbed for about 5-7 minutes until browned.

Once browned, reduce heat to medium and add minced garlic and sesame oil. Sauté for 1-2 minutes until fragrant. Then add soy sauce, sugar-free sweetener, rice vinegar, crushed red pepper flakes, and ground ginger.

Remove from heat and stir in half of the chopped green onions and sesame seeds. Plate the beef mixture and garnish with remaining green onions and sesame seeds. Serve alongside cucumber salad.