Flooring can be run under the cabinets, or but up to them. I prefer, after years of experience, not to run floors under the cabinets. This allows floor repairs or replacement without removing the cabinets. This is especially important if you use expensive heavy counters like granite or cast in place concrete. But I have done it both ways. With the cabinets in place and shimmed to the final floor level, laying a ceramic floor up to the cabinets (masked for protection) is easy. The layout is easier because you can plan not to have a groutline or sliver of tile at the cabinet edge. ON the other hand, laying the floor wall to wall before the cabinets are installed is easy, involves less cutting, but is more wasteful of finish you will never see.