How to Make It
Preheat the oven to 400°. Set a rack over a foil-lined rimmed baking sheet. Arrange the bacon strips on the rack and bake until browned and crisp, about 25 minutes. Transfer the bacon to paper towels to drain.
In a measuring cup, combine the vegetable oil with the olive oil. On a work surface, top the garlic with a generous sprinkle of salt and smash to a paste with the flat side of a knife; scrape into a bowl. Whisk in the egg yolk, 1 1/2 teaspoons of the lemon juice and 1 teaspoon of water, then slowly whisk in the oil mixture so the aioli thickens.
Season the aioli with salt, pepper and the remaining 1 teaspoon of lemon juice.
Spread the aioli on each slice of toast. Arrange the tomatoes and arugula on
4 of the toasts; sprinkle with salt and pepper. Top with the bacon, close and serve.