Wall Tiling
After removing the original Sharp microwave, Jan and I decided to put up tiling on the kitchen and bathroom sink walls before we installed a new microwave.
But how do you fasten tile so that it doesn’t come loose in an RV?
Once again someone on a RV forum, www.rv.net I think, suggested Flex-Tile. The owner was helpful and very interested in my project. He sells a rubber silicone adhesive to fasten the tiles and a white or gray silicone grout. We opted for the gray, but I think the white might have been a better choice.
Besides the silicone, we also bought from Flex-Tile a hard rubber float to apply the grout and wipe up sponges to remove the grout. The tiles came from Home Depot.
Working with silicone is much different than working with traditional tile adhesives and grout. You really have to work to get silicone grout completely off — lots of elbow grease involved. Then you’ll have to live with the smell of drying silicone for a few weeks.
We were pleased with the results — not knock-your-socks-off — but happy that the tiles looked a lot better than the previous surfaces . . .
rvSeniorMoments 
It looks as though you’re previous microwave was also a convection oven, and the new one appears to just be a microwave. Maybe there is something I am not seeing in the pictures, but do you no longer have an oven?
The new one is also a convection microwave.