In a small pot, combine the rice, 1 cup of water and a big pinch of salt. Bring to a boil then cover and reduce the heat to low. Simmer 15 minutes. Remove from heat and fluff with a fork. Set aside.
Place poblano peppers on a sheet pan. Roast in the oven for 10-15 minutes, or until the skin is browned and blistered. Remove from the oven and set aside to cool, leaving the oven on. When cool enough to handle, make a lengthwise slit in each pepper and remove and discard the ribs and seeds.
While the peppers cool, in a large skillet, heat oil on medium-high until hot. Add garlic and onion. Cook, stirring frequently, 2-3 minutes, until softened. Stir in the tomato paste and cumin. Cook, 2-3 minutes. Add ground beef. Cook, breaking the meat apart with a spoon, until cooked through. Stir in the currants, pepitas and cooked rice; season with salt and pepper, to taste.
Stuff each pepper with the filling. Bake 4 to 6 minutes, or until heated through. Remove from the oven.
While the peppers bake, in a small bowl, combine Mexican crema, lime juice, half the cilantro and 1 tablespoon of water. Season with salt and pepper to taste.
Drizzle the peppers with lime crema and sprinkle with remaining cilantro. Enjoy.