Can I omit interface methods which I do not use in Kotlin?

Sure, that is possible! you can implement one interface method when you extend it, all you have to do is to provide a default implementation for the other methods in the interface declaration

interface EventHandler {
    fun onSee()
    fun onHear() { /* default implementation */ }
    fun onSmell(){ /* default implementation */ }
    fun onTouch(){ /* default implementation */ }
    fun onAwake(){ /* default implementation */ }
    fun onSleep(){ /* default implementation */ }
}

Now when you create an instance of this interface you only need to provide a compulsory implementation for onSee() method, rest are optional

If you’re not the author of the original interface
You could extend the original interface and provide a default implementation for the methods you want

interface OnSeeEventHandler: EventHandler {
    override fun onHear() { /* default implementation */ }
    override fun onSmell(){ /* default implementation */ }
    override fun onTouch(){ /* default implementation */ }
    override fun onAwake(){ /* default implementation */ }
    override fun onSleep(){ /* default implementation */ }
}

And use the OnSeeEventHandler to provide only onSee method imeplementation