In a very large skillet, heat 2 tablespoons of the olive oil. Add the garlic and cook over moderate heat, stirring, until fragrant, about 30 seconds. Add the collards and arugula in large handfuls, letting each batch wilt slightly before adding more. Cook, tossing frequently, until the collards start to soften, 5 to 7 minutes. Add the lemon zest, lemon juice and crumbled chiles, season with salt and toss to evenly coat the greens. Remove the skillet from the heat and stir in the remaining 2 tablespoons of olive oil. Transfer the greens to a serving platter, top with the peanuts and serve.