I'm making Kimchi for the first time and I have two questions about air bubble removal. First, all the recipes I've seen say to press the Kimchi down to remove air bubbles. My batch had a few small bubbles lower in the jar, probably the size of a lentil or less, and when I tried pushing down deep enough to get them out, it tended to just introduce more air bubbles around the muddler I was using to press it. Short of putting the jar in a centrifuge, I don't see how I could get these small bubbles out. How strict should I be about initial air bubble removal? Is it ok to have a few very small bubbles like the one highlighted below?  Second, I see after the first day that some larger bubbles have formed lower down in the jar. This picture shows a larger bubble after 24 hours of fermentation which was definitely not there when I initially jarred and packed the veggies down:  Recipes I've seen tell you to push the solid contents down below the surface of the brine periodically as it ferments. Should I also try to remove new/larger bubbles as they form during fermentation? I.e. by pushing deeper into the jar with a muddler. Or does doing so risk contaminating the environment with new external bacteria? 
Small air bubbles are normal and make no difference to kimchi fermentation, nor do larger bubbles that form during fermentation. As long as the kimchi remains more or less submerged in the liquid, there’s no need to remove the trapped gas. Kimchi is an extremely difficult thing to mess up - once established, the lactic acid bacterial culture will murder any microbes that get in its way - so i think that manually degassing it would probably be okay, but it would serve no purpose. 