Preheat the oven to 375°F. Arrange the bacon on a broiler pan; bake until crisp, 15 minutes. Let the bacon cool, then reserve eight slices and finely chop the rest.
In a medium size bowl, stir together the chopped bacon, cream cheese, scallions, radishes, carrot, celery, red pepper and garlic.
Slather the bagel bottoms with the cream cheese mixture. Top each with two slices bacon, two lettuce leaves and a slice each red onion and tomato. Season with salt and pepper and add the bagel tops.