Cook the bacon in a large skillet over medium heat. Transfer the bacon to paper towels to drain and reserve bacon drippings in a small bowl.
In the bowl of a food processor, pulse together chickpeas, tahini, 1 tablespoon reserved bacon fat, lemon juice and chopped garlic, scraping down the sides and pulsing just until smooth.
Add the water, 3 slices of chopped bacon and 2 tablespoons chopped scallions. Pulse it a few more times until combined, and then season with salt and pepper.
Transfer the hummus to a serving dish and garnish with remaining chopped bacon and additional chopped scallions.