Quick question: are you thinking what I think you are thinking? Why make a sauce-less lasagna? Is sriracha the savior of any meal? Are my glasses too hipster? Maybe not the last two. Maybe that is just me. Maybe not. I'm not here to settle those questions, though, just the first one. You may want to make a lasagna with no sauce because, say, you are using a lot of liquidy ingredients and fresh noodles (which won't soak up as much liquid). Or, because no one makes a can of pasta sauce in anything approaching a reasonable size and you hate wasting food. You might have other reasons; I'm not one to judge. But, should you ever decide to make one, I've got some tips.
The general gist of our lasagna was slicing and sauteeing all the mentioned vegetables (except tomatoes) and making about 1/2 cup of pesto from scratch using a mortar and pestle. We then made 3 layers of pasta sheet, veggies, bit of grated cheese, pesto. On top we put sliced tomatoes and more cheese, plus a few extra leaves of basil for kick. Cooked for about 40-45 minutes in a 350 degree oven. Was rather delicious, if not filling in the least. Also rather messy, as you can see from this (horribly taken, horribly fixed up) photo below.