Bring a large pot of salted water to a boil. Add pasta and cook according to package instructions.
While the pasta boils, pre-heat the oven to 425. Line a baking sheet with parchment paper and spread the lemon slices evenly on the paper. Bake for 15 minutes until edges are starting to brown.
Place the cooked pasta in a large bowl with the baked lemons, red onion, cherry tomatoes and parsley.
In a measuring cup, combine the tahini, lemon juice, and olive oil. Season to taste then pour over pasta mixture. Toss until all ingredients are coated.