Preheat the oven to 375.
Cut each vegetable into cubes and toss with a splash of olive oil, salt & pepper. Spread on baking sheets, grouping individual vegetables together. This will ensure that if one vegetable is taking longer to roast you can pull it out.
Roast them for 20-40 minutes. Toss periodically until the veggies are tender and slightly golden on the edges.
If you are assembling the burritos to be wrapped in foil, prepare pieces of foil just larger than your tortillas.
Warm the tortillas in a skillet over low heat. As soon as they are hot, smear on the refried beans, top with a medley of roasted vegetables and dollop of salsa. If desired, sprinkle on a few pieces of chicken and shredded cheese.
To wrap the burritos:
Place on the tortilla on the foil.
Fold the right and left sides together, about half way to the center. Hold them together and then fold the bottom side up while tucking in the filling ingredients. Continue to roll up until the burrito is formed with both ends folded inside.
Wrap the foil around the tortilla, twist and tuck the ends in.
If the burritos are semi-warm, bake them for 15 minutes until just too hot to touch. Serve.
To freeze and heat:
Store the foil wrapped burritos in a large freezer bag. Freeze for up to two months. To heat, defrost at least 4 hours and bake for 20-30 minutes at 375. Alternatively, bake from a frozen state for about 35-45 minutes until the center feels hot to the touch.