Herby Smoked Salmon Fattoush

Name: Herby Smoked Salmon Fattoush
Ingredients: 1 clove garlic; 1/4 cup olive oil; 1 medium lemon; 1 tablespoon ground sumac, plus more for serving; 1/2 teaspoon kosher salt; 1/4 teaspoon freshly ground black pepper; 1 medium romaine lettuce heart; 1/2 medium English cucumber; 4 medium radishes; 2 medium scallions; 1 cup cherry or grape tomatoes; 1/4 cup packed fresh basil leaves; 1/4 cup packed fresh mint leaves; 1/4 cup packed fresh parsley leaves; 1/2 (7 to 8-ounce) bag pita chips, preferably multi-grain (about 2 1/2 cups); 4 ounces feta cheese; 2 (4-ounce) hot smoked salmon fillets