Preheat the oven to 400 degrees F.
In a large bowl, stir the zucchini, yellow squash, tomatoes, and peppers with 2 tablespoons olive oil, 1 teaspoon kosher salt, 1/2 teaspoon black pepper.
Spread the vegetables across 2 sheet pans in a single layer. Arrange the tomatoes cut side up.
Roast the vegetables until the zucchini, squash and peppers are lightly browned at the edges and the tomatoes are wrinkled, about 25-30 minutes, rotating the pans halfway through roasting.
While the veggies are roasting, simmer the pasta in a large pot of salted boiling water until al dente according to package instructions. Drain and rinse with cold water in a colander.
For the vinaigrette, whisk the garlic, mustard, honey, oregano, red pepper flakes, salt, pepper, vinegar, lemon juice and olive oil in a small bowl.
In a large bowl combine the pasta, roasted vegetables, baby spinach, red onions, feta, walnuts and parsley.
Drizzle with half the vinaigrette, tossing to combine. Add more dressing as desired.