1 cup water
2/3 cup whole-wheat couscous
1/2 cup nonfat plain Greek yogurt
2/3 cup shredded seeded cucumber
3/4 teaspoon garlic powder, divided
1/4 teaspoon salt
3/4 cup silken tofu
1 10-ounce package frozen chopped spinach, thawed and squeezed dry
2/3 cup crumbled feta cheese
1/4 cup snipped fresh dill
1/4 cup minced red onion
1/2 teaspoon freshly ground pepper
2 tablespoons extra-virgin olive oil, divided
4 cups sliced or torn green leaf lettuce
Grape tomatoes, halved, for garnish