Soak the rice in hot water for 5 minutes, then rinse with cold water and drain well
While the rice is soaking, puree the tomatoes, onions, garlic, chili powder and salt, in the blender and set aside.
Heat the oil in the skillet over medium-high heat and toast the well-drained rice, about 3-4 minutes, until the rice has turned milky white and feels like the grains have hardened when you stir it around.
Add the tomato puree, stir to coat the rice thoroughly and absorb into the rice, about 2 minutes.
Add the warm chicken stock to the skillet with the lime juice, gently stir and arrange the cilantro sprigs on top of the rice.
Bring to a boil, then reduce the heat to low. Cover the skillet and simmer the rice, about 18-20 minutes.
Check the rice for doneness and seasoning. If it needs to cook a bit more, make sure there is some liquid in the pot. If not, add a couple of tablespoons of water, cover and cook a few minutes more.
Let the rice sit, covered, for 5 minutes before fluffing with a fork.