Steak Kebab Bowls

Name: Steak Kebab Bowls
Prep time: 30 min
Total time: 30 min
Cuisine: Middle Eastern
Ingredients: 1 lb. sirloin steak, cut into 1 1/2" cubes; 1/2 tsp. dried oregano; 1/4 tsp. crushed red pepper flakes; 7 tbsp. extra-virgin olive oil, divided; 2 tbsp. fresh lemon juice, divided; 3 tsp. grated garlic, divided; Kosher salt; 1/4 c. smooth tahini; 1 tsp. honey; Freshly ground black pepper; 8 oz. dried orzo (about 1 1/4 c.); 2 1/2 c. (or more) low-sodium chicken broth; Neutral oil, for grilling; 1 red onion, cut into 1 1/2" pieces; 1 large yellow or orange bell pepper, seeds and ribs removed, cut into 1 1/2" pieces; 10 oz. grape tomatoes (about 2 c.); 4 Persian or 2 English cucumbers, thinly sliced into quarter-moons; 5 oz. baby spinach; 1 small bunch fresh chives, finely sliced