Aside from the aesthetics, it's really poor practice to put any kind of plaster/texturing on top of wallpaper -- he really shouldn't have done that. It will not last, and is only as durable as the paper underneath it. Honestly, no professional who knows anything about wall construction would have done this. :-( If at all possible, and I know it must be hard to contemplate, please do tell him this is unacceptable work and he really has to take it down to the drywall, whether he wants to do texture or smooth afterwards. And clearly smooth is the way to go in a kitchen. I had a textured kitchn once, in California, and I hated how it always looked grungy no matter what. You can try matte paint, but the problem is that you really need scrubbable paint in a kitchen, especially with texture that will trap any smoke/grease/dirt. So sorry! But hopefully you can appeal to his professional pride and have him re-do it. You're paying a lot for a remodel, you don't want the foundation to be half-arse. :) If you absolutely cannot get him to change it, I'd recommend Benjamin Moore's Aura paint in flat, which is the most scrubbable of the matte finish paints that I know of.

My thoughts on the order of attack are: 1. Use putty knife to get in behind it to the plaster in a small inconspicuous area just to get a better grip on what I'm working with. 2. Water/Fabric Softener out of a pump sprayer. If it soaks in, let it sit for a while and see if it comes off with a putty knife or scraper. 3. Try this product from Amazon (link at bottom) - EcoSolve Home Strip X-Tex Textured Coatings Remover 4. I'm going to be renting a steamer for all of the wallpaper in the home and will maybe give that a go as well. 5. If none of the above works, I will try to sand. If this works, I will likely rent a power sander/vacuum combo. 6. If all else fails, I will skim coat with joint compound. Does this sound reasonable? Here is a link that might be useful: EcoSolve Home Strip X-Tex Textured Coatings Remover

I have to agree with BeverlyFLaDeziner, the walls of the Chicago Art Institute are covered with painted over canvas. Makes a great back drop for million dollar master works! True canvas was used early in the last century, even in brand new construction. It helped hide the spider cracks so common with plaster of that era. It also assured that the heavy build up of paint over the decades could be simply pulled off the wall, leaving virgin plaster once again. For anyone contemplating extensive wallpapering, the best thing one can do is put a coat of low sheen OIL enamel on those walls first. Years down the road, you will smile at your foresight! I did this to my last home which had extensive wallcoverings, and in the 30 years I was in that home, I patted myself on the back every time I changed one of the wallcoverings. Granted, my labor was "free".

In the Boston area all gypsum board is normally finished with "veneer plaster", commonly called "blueboard" since the gypsum board is a blue-grey color. In its simplest form, its an 8th of an inch thick skim coat of real plaster (not joint compound) troweled on by hand. The finishers use special hinged stilts and make sweeping motion with the trowel and move unbelievably fast. Its usually cheaper then taped drywall because it requires less time and there is no sanding. It does require more skill but its easy to find in this area probably because of the plaster tradition brought over from the old country (primarily Ireland) that shifted from horsehair plaster to veneer plaster in the 50's and 60's. At any rate, no one wants taped drywall after seeing veneer plaster. It can have any texture you want but I've never seen it other than smooth. Its so beautiful I've see it left unpainted. Its more difficult to damage the surface, easy to rear and paint lasts much longer. If you drive west of Boston it doesn't take long for it to no longer to be available. Someone could make a fortune spreading this skill across the country. Here's a link to a video from Ths Old House. Ads from Home Depot: