I mean, you probably don't have to worry too hard about oxalates! The strongest predictor by far for stone forming is a history of stone forming, so
I have to be very careful to limit oxalate-rich foods, but unless you've had problems before, you're likely good - although it's still not a bad idea to keep it in mind, because kidney stones suck a
lot to have. And be sure to drink plenty of water, of course, but that's a good rule no matter what.
Another way I like to use vegetables is in sauces. It doesn't take much - what I'll usually do is start with a Béchamel (blond roux, add milk or cream) and then once it's well combined add handfuls of well-chopped onion, bell pepper, mushroom, or almost anything else I have on hand. Simmer and stir over low flame until the flavor and texture say "done". If you like spicy, then adding one whole finely minced habanero early on makes for a pleasantly gentle and slow-working heat; if you like umami, a generous dose of gorgonzola or some other strong cheese gives the sauce a unique base note. The juices from the vegetables (especially mushrooms, which are full of water) will join the sauce, bringing their volatiles along, and you end up with a subtle flavor that, depending on what you put in, will complement just about anything.
(If you eat meat and like steak, do be sure also to try it under a mushroom-and-gorgonzola sauce on this base! "That's got to be way too much" of both is about enough, and you can also add fresh crumbled bacon. Done right, it beats out any steakhouse I've ever been to. Enjoy!)