move and fire mobile

So, I am almost finished with my first game. If I want to make it just playable on a PC then it's done but I'd like to port it to mobile and make it available on the android store. The problem is that I can't get the movement and fire to work. I know it needs to recognize the difference between a tap and holding down. the question is how...? Below is my movement and fire portion of the script. Any assistance would be greatly appreciated.

 void Update () {
 //below will pull information for the inputs
     float xAxis = Input.GetAxis ("Horizontal");
     float yAxis = Input.GetAxis ("Vertical");

     //Change transpos based on axes
     Vector3 pos = transform.position;
     pos.x += xAxis * speed * Time.deltaTime;
     pos.y += yAxis * speed * Time.deltaTime;
     transform.position = pos;

     bounds.center = transform.position;

     Vector3 off = Utils.ScreenBoundsCheck (bounds, BoundsTest.onScreen);
     if (off != Vector3.zero) {
         pos -= off;
         transform.position = pos;
     }
     //Ship rotation
     transform.rotation = Quaternion.Euler (yAxis * pitchMult, xAxis * rollMult, 0);
     //to fire
     if (Input.GetAxis("Jump") == 1 && fireDelegate != null) {
         fireDelegate();
     }
 }