1. In a large nonstick skillet, warm vegetable oil over medium-high heat. Add onion and zucchini, sprinkle with brown sugar, and cook, stirring, until vegetables are softened and beginning to brown, 8 to 10 minutes.
2. Add garlic and stir until aroma is released, about 30 seconds.
3. Place beans in a medium bowl and mash them slightly with a fork or the back of a spoon. Add to skillet along with corn and chipotle seasoning and stir to combine well. Cook, stirring frequently, until filling is heated through, 2 to 3 minutes.
4. Wrap tortillas in paper towels and warm in microwave on High for 30 to 45 seconds. Place tortillas on plates and divide cheese and tomatoes.
5. If using, prepare tuna or pork. For tuna, wipe skillet clean, then add vegetable oil and heat over medium-high heat. Season tuna with salt and black pepper. Cook tuna, turning once, until desired degree of doneness (about 2 minutes per side for rare tuna, 3 minutes for medium-rare). Discard skin and slice cooked tuna thinly, then divide among 4 burritos, placing slices on top of diced tomatoes. For pork, heat in microwave for 1 1/2 minutes, then divide among 4 burritos, placing slices on top of diced tomatoes.
6. Working from the bottom, roll tortilla up over ingredients. Fold in ends and continue to roll. Serve with seam down.
Nutritional value is based on the vegetarian version of this recipe.
Source: Hannaford fresh Magazine, March - April 2009