Greek Salmon Couscous Bowls

Name: Greek Salmon Couscous Bowls
Ingredients: 6 skinless salmon fillets (about 6 ounces each); 3 1/2 tsp. kosher salt; 1 tsp. black pepper; 1 3/4 tsp. dried oregano; 2 tbsp. red wine vinegar; 1/4 tsp. red pepper flakes; 2 garlic cloves, finely chopped; 3/4 c. plus 1 tablespoon olive oil; 2 bell peppers (1 green, 1 red), cut into 1/2-inch pieces; 1 cucumber, seeded and cut into 1/2-inch pieces; 1/4 red onion, thinly sliced; 1 1/2 c. couscous; 6 oz. feta cheese, crumbled; 1 c. pitted assorted olives, halved; 3/4 c. tzatziki