Combine the masa harina, 1/4 teaspoon salt, and ground red pepper, stirring well with a whisk. Add 1 cup boiling water to masa mixture, and stir until a soft dough forms. Cover until ready to use.
Heat a 9-inch cast-iron skillet over medium-high heat. Add olive oil to pan; swirl to coat. Add beef to pan; cook 5 minutes or until browned, stirring to crumble. Add onion, garlic, poblano chile, remaining 3/4 teaspoon salt, and black pepper to pan; sauté 5 minutes or until onion is tender, stirring frequently. Add tomatillos and lima beans to pan, and cook for 2 minutes. Remove from heat.
Add butter and baking powder to masa mixture, stirring until smooth. Dollop batter over filling, and spread into an even layer. Cover pan with foil; bake at 400° for 30 minutes. Uncover and bake an additional 10 minutes or until crust is lightly browned around edges. Remove from oven; let stand 3 minutes. Sprinkle with crumbled queso fresco and cilantro; serve with lime wedges.