1. Cook bacon in a nonstick skillet over medium-low heat until golden brown. Drain on paper towel. Reserve 2 Tbsp bacon fat.
2. Preheat oven to 350°F.
3. Toss bread cubes with bacon fat, thyme, salt, and pepper. Spread in a single layer on a rimmed baking sheet and bake until golden, 12-15 minutes, shaking pan once.
4. Place arugula and frisée in a bowl. Toss with bacon, tomatoes, bread cubes, chives, salt, and pepper. Drizzle with dressing.