Cook pasta
Place 1 tbs olive oil and garlic in a large skillet. Cook over medium heat, stirring occasionally, until the garlic is sizzling and fragrant, 2 to 5 minutes. Add sweet potato, bell pepper, tomatoes and water and cook, stirring occasionally, until the bell pepper is tender crisp, 5 to 7 minutes. Remove from the heat, cover and keep warm.
Drain the pasta, reserving 1/2 cup of the cooking water. Return the pasta to the pot. Add the vegetable mixture, the remaining 1 tbs olive oil, parsley, tarragon vinegar (or lemon juice), salt and cheese: toss to combine. Add the reserved pasta water 2 tbs at a time to acheive the desired consistency.