In a skillet, heat 1/4 cup oil over medium-high heat. Add the onion and cook, stirring frequently, until soft, about 5 minutes. Add the garlic and cook for 30 seconds until aromatic. Add the cherry tomatoes, artichoke hearts, olives, sun-dried tomatoes and thyme. Cook, stirring occasionally, until the tomatoes begin to soften, about 8 to 10 minutes toss in the tuna and cook about 2 to 3 minutes. Add the pasta, the remaining 1/4 cup olive oil, feta cheese, olive brine and the parsley. Toss until all the ingredients are coated, adding a little pasta water, if needed, to thin out the sauce. Season with salt and pepper, to taste. Transfer the pasta to a serving bowl and serve warm or at room temperature.