Heat a gas grill to medium or light a charcoal grill and let it burn until the coals are medium-hot and covered with gray ash.
Lay the halved tomatillos cut-side down on a rimmed baking sheet or metal baking pan and slide the sheet onto the grill. Brush the ramps (or green onions or garlic chives) with oil. Lay them directly on the grill, along with the Serrano or jalapeo (no oil needed). Grill the ramps (or their stand-ins) and the chile, turning occasionally, until soft and richly browned the ramps will take 4-5 minutes, the chile about 10.
Cook the tomatillos about 3 to 4 minutes, until soft and browned on one side, then flip them over and cook on the other side. Cool everything.
Finely chop the ramps and chile, then scrape into a large bowl. Chop the tomatillos into small pieces and scrape them in with the ramps, then scrape in any juice that remains on the baking sheet.
While the grilled vegetables are cooling, cook the bacon in a single layer in a large skillet over medium heat, turning every once in a while, until browned and crispy, about 10 minutes. Drain on paper towels, then chop into small pieces.
Cut the avocados in half lengthwise. Remove the pit, then scoop the flesh from each half into the bowl with the tomatillos. With an old-fashioned potato masher, a large fork or the back of a large spoon, coarsely mash the avocado with the tomatillo mixture. Stir in the lime juice, cilantro and half of the bacon. Taste and season with salt, usually about 1 teaspoon. Cover with plastic wrap pressed directly on the surface of the guacamole and refrigerate until youre ready to serve.
To serve, scrape the guacamole into a serving dish and sprinkle with the remaining bacon. Garnish with cilantro leaves.