Pour boiling water over the ancho chiles in a bowl; cover and set aside 10 minutes. Meanwhile, heat 2 tablespoons vegetable oil in a medium saucepan over medium-high heat. Add the rice and cook, stirring often, until golden, about 3 minutes. Stir in the poblano and chopped garlic and cook until the poblano starts to soften, 3 minutes. Add 11/2 cups water and 1/2 teaspoon salt. Bring to a boil, then reduce the heat to low; cover and cook until the rice is tender, 20 minutes.
Meanwhile, drain the anchos and remove the stems and seeds. Puree the anchos, smashed garlic cloves, 1/2 cup water, the tomato sauce, oregano, cumin, 1/4 teaspoon salt and a few grinds of pepper in a blender. Heat the remaining 2 tablespoons vegetable oil in a large skillet over high heat. Add the ancho puree and cook until the sauce is reduced, about 5 minutes. Stir in 1 cup water and the shrimp. Return to a boil and cook until the shrimp are opaque, about 5 minutes. Season with salt.
Fluff the rice with a fork. Top each serving with the shrimp, sauce and desired toppings. Serve with the tortillas and lime wedges.