I love the random natural beauty of slate floor tile. I have already purchased the type i want. Plan on having one counter butcher block for carving. Question is how to finish tile, should i grind/sand top to a more even level, can i leave little/no space for grout and what is the best method of sealing?

are you talking about using the slate for the counter. No can do.. Its way to soft for a counter and it cannot be properly sealed to prevent bacteria from setting into the stone. Hot surfaces that come in contact with this will cause the stone to spall.

But to answer your question about level etc.
The stone should be set into a layer of cement type thinset. This material is put down in various thicknesses to allow the top of the stone to remain level. You do not grind the top of the stone at all.
In regards to the space between the stone the less is best. The bigger the joints the easier it will crack.
AS far as sealing the stone. There are many products out on the market. Check with the stone supplier based on the type of slate you purchased as they will provide the best answer to this question. Remember that the sealer will darken the color of the slate so be sure to check what this looks like before you set all the tile into place and end up not likeing it.

one of the nice things about natural stone is that there is such a great variation in the different stones. some are more pourous, some are extremely dense. some can be so dense that you wouldn't have to ever worry about sealers of any kind. If you like slate then you vermont slate is surly one of the ones you want to look at. very dense and any scratches are easily rubbed out. (let see you do that with corian or even granite) and several varieties and color variations. Ciciliot