Most modern jets like the ones you mention don't need or use more than idle thrust to taxi, although some have 'ground idle' and 'flight idle' modes.
For B737 and A320 I'd say use about 10kg/min. (assuming two engines running - my airline shuts one down for taxi in as a standard procedure, and I believe some larger jets will only start up nos. 3 and or 4 once taxiing out. I have no experience of those aircraft.)