Raw Mustard Greens Salad

5 anchovy fillets, finely chopped 3 garlic cloves, pressed 1/2 cup extra-virgin olive oil 3 cups 3/4-inch cubes crustless country bread 1 cup (packed) coarsely grated Gruyère cheese (about 4 ounces), divided Nonstick coconut  oil spray 1 bunch mustard greens (about 12...