Place vegetables in a large bowl. Drizzle with olive oil. Add in salt, pepper, red pepper flakes and cumin and toss until vegetables are coated with olive oil and seasoning.
Place vegetables in a grill basket and cook for 7-10 minutes until just slightly tender.
Cilantro-Lime Pesto
In a food processor combine cilantro leaves, lime juice, walnuts, Parmesan cheese and salt and pepper. Turn on high and stream in olive oil until blended.
Slice pitas and spread the inside of each pocket with a generous amount of pesto. Add in grilled vegetables and top with cheese.