I'm not vegetarian either, but bean quesadillas are always a good, cheap, and easy meal when I'm lazy. It can be as easy as open a can of black beans, drain and rinse, put on a big tortilla with cheese and some jarred salsa, cook both sides in a frying pan. If I'm feeling like doing a little more, I'll add some diced tomato and jalapenos. You can be eating in as little as 10 minutes.