using UnityEngine;
using System.Collections;

public class OnTouchDown : MonoBehaviour {

	foreach (Touch touch in Input.touches)
	{
		if (touch.phase == TouchPhase.Began)
		{
			// do staff when user just touch
		}
		else if (touch.phase == TouchPhase.Ended)
		{
			// do staff when user touch ended
		}
	}

}

Simple touch detection in unity for mob devices

Simple Touch Input

mobile, android

C#