I have been sealing the holes on our floor by cutting a small section of flooring out, gluing down a piece of aluminum flashing with a water proof caulk, then filling in almost level with additional caulk (I like the elastometric caulk for roofing repairs for that).
As for your choice of floor covering... From a food vendor... if you are using this kitchen to sell/serve food from, you had better check with your local Health Department... and don't forget the cove molding. Lowes/Home Depot sells a glue down commercial composition tile (12X12) By Armstrong (both stores I think). Tough stuff, we used in in the pop-up. It held up well to the dirt and clay in the campgrounds we stayed at. Only downside we found was the seams filled dirt unless we filled them with caulking. Yet this is preferred by Health Departments across the country over a solid vinyl floor. We plan on using it in our bus and putting "throw" rugs on top... when the rugs get too bad, I "throw" them away!