Preheat oven to broil. Place poblano peppers, cut side down, on a large baking sheet. Brush with vegetable oil. Broil for 3-5 minutes, or until skins are blackened and blistered.
Add roasted poblanos to a blender or food processor, along with the cilantro, onions, garlic and one tablespoons of the oil. Puree until smooth.
Heat the remaining oil on a large sauté pan over medium-high heat. Add rice and cook for 5-7 minutes, or until rice just begins to brown.
Add the pureed poblano mixture to the rice, along with the chicken broth and salt. Stir to combine, then bring to a boil over medium-high heat.
Reduce heat to a simmer. Cover and cook on low for about 15 minutes, or until the rice is tender and the liquid is absorbed. Remove rice from heat and let stand, uncovered, for 5-10 minutes.
Fluff rice with a fork, then mix in lime juice and additional cilantro before serving, if desired.