Plastic snap-lock containers do not leak. They don't need to be the "snaplock" brand per se--what you want is a container with a lid that has a gasket and tabs that snap around the base. Someone mentioned glass-base snaplock containers upthread--I don't have experience with these myself. I'm a little surprised to learn that they do leak. I understand there are reasons not to microwave in plastic; there are also reasons not to transport glass on a bike, so you need to choose which risk you want to take.

Ziplock containers absolutely do leak. Tupperware is a little better, but not great IME.

There are silicone food-storage bags that all seem to use a slide-on clamping rail to seal them. They're kind of spendy, but they are microwave safe and pretty rugged. I don't have any personal experience using them to transport liquids, but they might be worth checking out.