Bring a large pot of salted water to a boil over high heat. Add the orzo and cook until tender but still firm to the bite, about 7 minutes. While the pasta is cooking, place the oil in a large saute pan over medium low heat. Add the shallot and garlic and saute until the shallot begins to soften and the garlic is fragrant, about 1 minute. Add the tomatoes and warm through, about 1 minute. Add the warm tomato mixture to a large bowl along with the feta, arugula, mint, balsamic vinegar, salt and pepper. Drain the orzo, add it to the tomato mixture and toss to coat. Drizzle with the remaining 1/4 cup olive oil and serve.