Be forewarned: This lasagna is properly hot. If you "don't do spicy food," feel free to cut down the amount of chipotles en adobo, or to omit them entirely. But, if you're a fellow fire-breather like me, you'll notice that contrary to what a lot of people say about spicy food, the flavors don't get drowned out in this dish. That's because there are plenty of robust flavors to stand up to all the heat — freshly ground cumin, rich freshly grated Monterey Jack cheese, and poblano peppers charred over an open flame. It's all in the details on this one.
Char the poblano peppers one by one directly over a high gas flame, allowing each side to char completely black before turning with tongs. (You can allow the pepper to rest on the grating as you perform other tasks.) As each pepper cools, slip off the skin using your hands, seed, and dice finely.
Meanwhile, heat the oil over medium heat in a medium-sized saucepot. Add the garlic and cook until softened and golden brown, about 2 minutes. Add the tomatoes, chipotles en adobo, and cumin and simmer until the flavors meld and the sauce is thickened slightly, about 10 minutes. Remove from the heat and let cool.
Bring a large pot of salted water to a boil over high heat. Add the lasagna sheets and parboil for 4 minutes. Place parchment paper on 2 baking sheets. Drain and lay out the lasagna in a single layer on the baking sheets to keep them from sticking.
Transfer the tomato sauce to the bowl of a food processor and blend until the chiles are thoroughly incorporated. Stir in the cilantro and season with salt and pepper, to taste.
Preheat the oven to 350 degrees.
Place a layer of sauce in the bottom of a baking dish. Cover with a single layer of lasagna sheets, followed by the sauce, a handful each of Jack cheese, diced poblano pepper, and beans, followed by another handful of Jack cheese. Continue in this manner until all of the ingredients are used up, but save a little sauce and beans for the top.
Cover with foil and bake until the cheese is melted and the sheets soften completely, about 20-30 minutes. Remove from the oven and let cool for about 5-10 minutes before slicing and serving.