Rinse fresh chiles and pat dry. Place in a 10- by 15-inch baking pan and broil 2 to 3 inches from heat, turning chiles as needed, until blackened and blistered all over, 10 to 15 minutes. Let chiles cool about 15 minutes. Peel off as much of the skin as comes off readily. Cut a slit down one side of each chile; remove and discard seeds, leaving stems attached.
In a 10- to 12-inch nonstick frying pan over high heat, stir bacon until browned and crisp, about 5 minutes. Transfer bacon to paper towels to drain. Pour fat from pan into a bowl. Wipe pan clean with a paper towel.
In a bowl, whisk eggs to blend with 1/3 cup water, 1/2 teaspoon salt, and 1/8 teaspoon pepper. Set frying pan over medium-high heat. Add 2 tablespoons reserved bacon fat; reserve remaining for another use or discard. When fat begins to sizzle, tilt pan to coat bottom. Add egg mixture and sprinkle with 1 cup cheese, chives, and the bacon. When a thin layer of egg is set on pan bottom, in about 30 seconds, push cooked egg toward one side of pan with a wide spatula, letting uncooked egg flow underneath. Continue cooking and pushing until eggs are softly set but still moist, 3 to 4 minutes total. Stir to turn eggs over. Remove from heat.
Arrange chiles, slit side up, in a 10- by 15-inch baking pan. Fill evenly with egg mixture. Sprinkle eggs with remaining 1/2 cup cheese. Bake in a 400° oven until cheese is melted, about 3 minutes. Meanwhile, arrange tomato slices on plates. With a wide spatula, set chiles on tomatoes. Sprinkle with cilantro and crisp chile rings, if using; drizzle with chili oil to taste. Add salt and pepper to taste.
Crisp chile rings and oil. With a damp towel, wipe 1 dried guajillo or New Mexico chile (about oz.) to clean. With scissors, cut off stem; shake out as many seeds as possible. Cut chile crosswise into 1/8-inch-thick rings; drop into an 8- to 10-inch frying pan. Add 2 tablespoons olive or vegetable oil and stir over medium heat until chile rings are crisp and beginning to brown, 2 to 4 minutes; take care not to scorch.