Mix the veggies, flax seed, 1 1/2 cups cheese, and garlic into the cauliflower rice. In a separate bowl, mix together the ground beef and taco seasoning. Dump the ground beef mixture into the cauliflower rice mixture, and combine with your hands.
4 
Divide mixture evening among the peppers. Pour 2 cups of water into a slow cooker, and turn it on to low. Then place the peppers into the slow cooker and cover. Cook for 4 hours.
5 
30 minutes before you are ready to serve turn the temperature up to high. During the last few minutes of cooking, top each pepper with a remaining cheese.