1. In a small bowl, whisk together the vinegar, sugar, and 3 tablespoons (45 mL) of the olive oil. Season with salt and freshly ground pepper (but remember that the olives and ricotta salata are quite salty). Add the cherry tomatoes and toss to coat. Remove the pits from olives and cut in half. Toss the olives with the tomatoes and place on a serving platter.
2. Slice the ricotta salata into 2-inch (5 cm) pieces that are about 1/2 inch (1 cm) thick. Place in a bowl. Add the whole chilies to the ricotta, and toss with the remaining 2 tablespoons (30 mL) olive oil.
3. Heat a large cast iron skillet over high heat (or a chapa if you have one). Add the ricotta and chilies in batches, so they are not overcrowding the pan.
4. Cook for 10 seconds without moving, and as soon as you see the cheese turning a rich golden colour on the bottom, flip and cook the other side. Remove the chilies as soon as they blister and slightly char.
5. Roughly chop the chilies and break up the cheese. Place on the platter over the tomatoes and olives. Toss in the arugula, and sprinkle with the red chili flakes.