Android : Main Ignition App Hold Down Left Click

My company recently bought Motorola Droid phones for us to remotely adjust the amount of irrigation water released from a reservoir. To do this from a PC we place the cursor over the appropriate button on the screen and hold down the left mouse button. I can't figure out what to do to accomplish this on my phone. I've downloaded the log main ignition app and am able to remotely access the computer that controls the reservoir but can't hold down the button. Verizon is no help. They say there is probably an app for that but they don't know which one. Any suggestions