The ALMA calibrator database can be directly queried through a web form at http://almascience.org/sc/.

Alternatively, you can query the ALMA calibrator database from the OT in this way:

• Open up the OT and create a Science Goal (or use an existing Science Goal)
• Go to the "Calibration Setup" of the Science Goal 
• Select "User Defined Calibration"
• Select "Add fixed calibrator" and pick e.g. bandpass or phase

This brings up another interface.

• Select "Sideral Target"
• Click "Select from Source Catalog" 

This brings up a query interface you can use to find calibrators and their fluxes with dates.