Heat the vegetable oil in a large skillet over medium heat. Stir in the rice and toast it until it turns light golden, about 5 minutes. Then transfer the toasted rice into a greased slow cooker.
Add the tomato sauce, garlic salt, minced garlic, chicken broth, chili powder, ground cumin, and pepper to the slow cooker.
Stir the mixture well, cover, and cook on high for 2½ hours or until the liquid is absorbed and the rice is tender.
Gently mix in the lime juice and season with kosher salt if needed. Garnish with cilantro if desired.