Green Gazpacho with Spicy Croutons

Name: Green Gazpacho with Spicy Croutons
Ingredients: 4 slices day-old sourdough bread; 1 Teaspoon olive oil; 1 Teaspoon smoked paprika; 1 large cucumber, peeled, seeded, and chopped roughly; 4 large tomatillos, husked and chopped roughly; 1 large yellow bell pepper, seeded and chopped roughly; 1 small yellow onion, diced roughly; 2 Cups watercress, tough stems removed, chopped roughly; 1/2 Cup chopped cilantro; 1 Tablespoon kosher salt, plus more to taste; 2 1/2 Cups water, or to taste; Freshly ground black pepper, to taste