Vegetarian quick meals -
Someone mentioned quesadillas and they're really an endlessly changeable option.
You can do spinach, mushrooms, thinly sliced tomatoes, any roast peppers or asparagus or such, refried beans, etc.
Just lay out a tortilla, toss on a little cheese, add a layer of your whatever ingredient, some jalapeno if desired, more cheese, top with another tortilla and you can throw them in a hot oven for 15 minutes, do them in a sautee pan on the stovetop with a bit of oil, or on the grill.
You cam do a salad thing by keeping a bunch of different beans (whatever you like), some chopped onion, sliced mushroom, corn if you like, etc. marinating in the fridge in dressing. Then just take a bag of greens and chuck some of the bean mix on, add some cheese, toss, dinner.
You can also do a giant fruit salad. If you buy fruit and cut it all up at once (couple melons, pineapple, kiwis, berries, etc.) and store well, you can add some just-then stuff (apples, banana, etc.) and dish up big bowls and serve with greek yogurt. Take the plain yogurt, add a bit of honey or sweetner, some vanilla extract, and it's a fantastic fruit dipping thing, with lots of protein.