Sauté onions and garlic in oil for 2-3 minutes or until starting to soften. (I use my favorite pan
for this, if you don't have a big pan like that you may want to use less cabbage or it won't all fit.) Add optional celery and cook another minute or two, keep heat medium-low so onions or garlic don't burn. Brown optional sausage in that same pan. Once it's browned, add sugar and stir around. Add cabbage, carrots, and optional peas, stir-fry for 5 minutes or longer until cabbage is wilted. This will really fill up your pan at first, but as it cooks it shrinks and will be easier to stir around. Add soy sauce, sriracha, ginger, and red pepper, sea salt and pepper, and stir around. Add more of any of those for more flavor as needed when you taste-test.