In a large bowl, combine the tomatoes, 2 tablespoons olive oil, the vinegar, ½ teaspoon salt and ½ teaspoon pepper.
Bring a large pot of salted water to a boil, and cook the pasta to al dente according to package directions. Drain the pasta well and add it to the tomato mixture while still warm. Stir gently to combine, then let the mixture cool slightly.
While the mixture cools, in a large nonstick skillet, heat 2 tablespoons olive oil over medium-high. Pat the halloumi dry with paper towels, then cook it until golden-brown, stirring occasionally, 3 to 5 minutes.
Add the cucumbers, arugula (if using), cilantro, mint and red onion to the pasta; stir to combine. Top with the halloumi, then add more salt, pepper, olive oil and vinegar to taste. Serve immediately.
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