Cut the steak into equal chunks, 6 or 4. Season with salt and pepper.
On a skillet heat the olive oil over medium high heat. When hot, transfer steak and cook for about 3-4 minutes until both sides are brown.
Transfer steak to crockpot. Add onions and 1 cup of salsa verde. Mix gently.
Set the crockpot on low and cook for 8 hours or on high for 4 hours.
When cook time is complete, shred the been (in the crockpot) with two forks and mix with the salsa verde.
Serve the shredded beef over cauliflower rice and top with tomatoes and cilantro.