Pluck off the green stems from the cherry tomatoes, if any.
Place the cherry tomatoes into a colander/strainer and rinse them under running water. Shake off any excess water.
Lay a clean towel or cloth onto a flat surface. Empty the cherry tomatoes from the colander/strainer onto the cloth. Pat the tomatoes dry.
Pour the cherry tomatoes onto a baking sheet. Ensure they are evenly dispersed in a single layer, like in the image below. Don't overcrowd or pile the tomatoes on top of each other, or they'll freeze together in a clump.
Place the baking tray into the freezer and allow the tomatoes to freeze for 2 hours.
After at least 2 hours has elapsed, remove the baking sheet from the freezer.
Open a freezer bag or airtight container and fill it with the flash-frozen cherry tomatoes.
If you're using a freezer bag, gently press the air out of the bag and seal it. You don't need to use the "straw trick" here because the tomato skins do a pretty good job of protecting the tomato's flesh while in the freezer.
Write today's date on a freezer label, stick it to the bag or container, and place it in the back of your freezer.