Ceramic floor tiles are meant to be permanent so removing them is never going to be easy and you likely aren't going to be able to save the tiles for reuse. However, if you don't mind damaging the original tiles, with a lot of effort, you can remove ceramic tile.
Remove ceramic tiles set with mastic on a concrete base by first breaking up the grout around them (with a hammer and cold chisel) and then breaking the tiles with a sledgehammer. After the tiles are broken, slide a long handled floor scraper under the edge of the tiles and push forward. The pieces of tile should peel off the concrete base.
Scrape off any mastic residue.
Clean and vacuum the area and level the concrete.
Use a power-chipping hammer available from tool rental centers to first break up the grout around a single tile, and then work your way under the tile itself, breaking it up. Once you have removed the first tile, move on to the others. The job is easier if you start at an edge or a transition rather than in the middle of a tile bed.
Clean the area as best you can and then level the floor with concrete specifically designed to bond with old concrete.
Removing tile set on a backer board base requires removing both the tiles and the backer board.
Start at an edge or transition and remove the grout around a single tile (hammer and chisel) and then break up and remove the tile itself.
Remove three or four tiles in a section so that your have an area about six inches by six inches of the (now beaten up) backer board exposed.
Use a hammer to pulverize the backer board so it can be removed and you have an opening revealing the sub floor.
Slide a long handled floor scraper (or a flat tipped or roofing shovel) about six inches under the backer board but above the wooden sub floor, then push forward while lifting and turning the shovel.
Continue lifting up the backer board by sliding the shovel under it, until the board (and the attached tiles) has all been removed.
Repair any gouges made to the subfloor and then level it.
Removing an individual tile is much easier than trying to remove and entire tile bed.
Use a grout saw (or a hammer and chisel) to remove the grout all around the damaged tile.
Break up the damaged tile by carefully striking it with a cold chisel and a hammer.
Slide a stiff bladed putty knife under any pieces of tile that stick to the base and pry them off.
Clean up and repair the base in preparation for installing the replacement tile.
Knowing how much work it is to remove a ceramic tile floor, consider that you can install most types of flooring right over top of existing ceramic tile with a minimum of base preparation.
Always wear wrap around eye protection when trying to remove ceramic tiles and grout. Broken pieces of tile have razor sharp edges and you don't know where chips going to go fly when you're beating on the tiles with a hammer.