Preheat oven to 400˚. Dice zucchini and peppers into bite size pieces and remove corn from cob. Toss zucchini, peppers, and corn together with olive oil, salt, and pepper. Roast for 20-30 minutes until tender and beginning to brown.
Combine roasted vegetables, cooked buckwheat, cubed avocado, and goat cheese, if using. Whisk together lime juice and honey, drizzle over salad. Add in cilantro and toss everything together.