The produce I get in weekly CSA box are all quite unique. I get at least 3 different kinds of kale, 4 different kinds of lettuce, and so on. Even with the same kind of lettuce, sometimes it's young and pale and other times it's dark green and hard to eat raw (but it's yummy when sautéed). The carrots in winter are sweeter than the carrots in spring. Young onions are vastly different from normal onions.     The vegetables are all in high quality so I want to cook them with the most suited cooking approach (i.e., I don't want to simply substitute vegetables).  Is there any good website/cookbook that can help me search or learn more tailored approach to cooking different stages of vegetables?   I'm looking for a website/cookbook/other resources where I can continue to learn, rather than specific tips for specific vegetables. 
You may wish to seed the tomatoes, removing the gelatinous part containing the seeds, which is mostly water, and very little flavor.  You want to use only the meaty, fleshy part of the tomato in a quiche.    Depending on the size of your tomatoes, scooping the seeds out with a melon scoop, cutting out the seed sections, or simply squeezing out the seeds will help.  The Shiksa in the Kitchen has a very nice article with very clear pictures showing these three different methods of seeding tomatoes.  This will substantially reduce the amount of moisture the tomatoes are adding to your quiche.  Another method you may choose to use, if you have the time, is to roast your tomatoes before using them in the quiche (which may also involve seeding them first).  This will reduce the moisture and concentrate the flavor. 