Place potatoes in a pot, cover with cold salted water and bring to a boil. Boil for 8 to 10 minutes or until tender but firm. Drain well and place in a large bowl. Add onion and orange pepper.

Meanwhile, preheat barbecue grill to medium-high. Place steaks in a shallow dish and drizzle with 1 tbsp (15 mL) oil. Sprinkle with garlic, thyme and half of each of the salt and pepper. Turn to coat both sides. Grill steak, turning once, for about 5 minutes for medium-rare or to desired doneness. Transfer to a cutting board and let stand for 2 minutes, then thinly slice. Add to potato mixture.

In a small bowl, whisk together vinegar, horseradish and remaining oil, salt and pepper. Drizzle over potato mixture. Add basil and toss gently to combine. Spread arugula on a serving platter and spoon salad over top.Tip: This salad can be served warm or at room temperature. The bed of arugula absorbs the flavor of the salad as it sits.