How to Make It
If using salt-packed anchovies, rinse them under cold water. Place salt-packed anchovies in a medium bowl, cover with cold water, and let stand until pliable, about 20 minutes. Using your fingers, start where the body meets the tail, and pry open along the back, lifting out backbone to yield 2 fillets. Rinse fillets again to remove any fine bones; pat dry with paper towels. Finely chop cleaned anchovies. Using flat side of a large knife, drag knife back and forth over chopped anchovies to form a paste, chopping and dragging knife as needed to equal 3 tablespoons anchovy paste. Set paste aside; reserve remaining anchovies for another use.
Whisk together mayonnaise, 3 tablespoons water, lemon juice, cheese, garlic, fish sauce, pepper, Worcestershire, and 2 tablespoons homemade anchovy paste (or store-bought anchovy paste) until thoroughly blended. Whisk in more water, 1 tablespoon at a time, to loosen dressing as desired.
Preheat oven to 350°F. Place torn bread in a large bowl; set aside. Combine oil, garlic, and remaining 1 tablespoon anchovy paste in a saucepan; cook over medium, stirring often, until garlic is tender and mixture is very fragrant, 3 to 5 minutes. Drizzle over bread, and gently toss until oil is absorbed. Sprinkle with salt and pepper. Arrange croutons in a single layer on 2 rimmed baking sheets. Bake on separate oven racks in preheated oven until browned and crisp, 15 to 20 minutes, stirring croutons and rotating baking sheets (top to bottom) halfway through baking time.
Gently toss together romaine, frisée, and 1/2 cup dressing in a large bowl. Reserve remaining dressing for another use. Season with salt. Add onion, herbs, and figs; toss to combine. Divide salad mixture among 4 plates. Top salad evenly with croutons, cheese, and anchovy fillets. Drizzle chile oil and lemon juice evenly over salads.