Heat a grill to medium-high (400° to 450°). Cook orzo according to package directions. Drain, then set aside.
Brush steak and cheese with 2 tbsp. oil and sprinkle steak with salt. Grill both, turning once, until grill marks appear on cheese, and steak is done the way you like, 8 to 10 minutes for medium-rare. Let steak rest 10 minutes.
Cut halloumi slices into quarters. Combine cheese, orzo, remaining 4 tbsp. oil, and remaining ingredients in a bowl; divide among 4 plates. Top with sliced steak.