Start by preparing your ingredients. Wash the tomatoes, red bell peppers, celery stalks, and cilantro leaves thoroughly.
Roughly chop the tomatoes and red bell peppers, ensuring they are small enough to fit through the feed chute of your juicer.
Slice the celery stalks into smaller pieces. Peel the ginger and slice it into thin strips.
If you're using jalapeño for an extra kick, remove the seeds and stem, and chop it finely.
Turn on your juicer and begin feeding the tomatoes, red bell peppers, celery, ginger, and jalapeño (if using) through the juicer. Do this step in batches to prevent overloading the machine.
Once all the vegetables have been juiced, stir in the fresh lemon juice, salt, and ground black pepper.
Taste and adjust the seasoning if necessary. If you prefer a thinner consistency, you can add a small amount of water to the juice and mix well.
Pour the juice into glasses over ice cubes if desired, and garnish with fresh cilantro leaves.
Serve immediately for the freshest flavor, or store in an airtight container in the refrigerator for up to 24 hours.