onions are a great foundation
'Why not start with onions? Onions are a great foundation to so many meals.' This is how my conversation with my daughter starts as she takes on creating watercolors of the many types of vegetables.
They may make you cry when you chop them. Who doesn't need a good cry? When they sweat in the pan they add incredible savory flavor not to mention health benefits! There are so many kinds of onions! some types of onions one can start with:
scallions + leeks + shallots + vidalia + spanish + red + yellow + cipollini +...
Good luck with your onions, have fun chopping them! I suppose if you aren't into them, it doesn't have to be onions. If you don't want to start with onions you can start with something else. Try the brassicas or greens straight in oil or water!