Grease a slow cooker with cooking spray.
Heat oil in large frying pan on medium heat. Add rice and cook until golden brown (about 5 minutes).
Remove rice from heat and add to the slow cooker.
Pour in tomato sauce, salt, minced garlic, chicken broth, cumin and pepper and stir to combine.
Cover and cook on high for 2½-3 hours or until the liquid is gone.
Add fresh, chopped cilantro, if desired and serve warm.