Put soy sprouts in boiling water and cook for 5 minutes, then cool.
Wash the lettuce leaves and tear them into small pieces by hand.
Coarsely chop cucumbers and tomatoes, chop parsley and onion.
For the sauce, mix balsamic vinegar and mustard seeds, add olive oil.
If there is no balsamic vinegar, use soy sauce, lemon juice and apple or grape vinegar.