Rinse the rice under cold water until it runs clear.
In a pot, combine rice and water or broth; bring to a boil.
Reduce heat to low, cover, and simmer for 15-20 minutes until rice is cooked.
While the rice cooks, brown the ground meat in a skillet over medium heat.
Add diced onions to the meat and sauté until translucent.
Stir in taco seasoning and a little water; simmer for 5 minutes.
Once the rice is done, fluff it with a fork and set aside.
Layer the rice on plates, then top with the seasoned meat.
Add diced tomatoes, shredded lettuce, and cheese on top.
Serve with lime wedges and optional jalapeños.