Temporarily you can lay a thin bead of caulking it will come off both the fridge and counter cleanly. Not seeing the issue and possible space it's difficult to advise you further. Possible to take a picture?

@Nitin : One more thing is where to keep washing machine. if basin counter occupies the 4ft wall , then I will be forced to keep the washing machine on the 5ft wall side.

Hi Sumit, there are two different concepts I am sharing hereby: ONE with Charcoal Grey on the wall since your counter top is greyish in texture it will blend well & with right light fixture will look eclectic! SECOND with whites leading to RED standing out as pop color!

Try to keep a band ( designed metal or board ) around the sink on three sides , which can makes the water spill less on that three sides ....or try to keep a rectangular hole on corners around sink for slab which doenst look like hole and get a decorative cover for that, and connect that to the outlet at down...so that its easy to push water around the sink so that it drains... Or get an extra slab just to place around sink where water spills and place it on top of existing slab if you don't want to remove the existing sink and place...