Positional motifs and training websites/softwares/apps? Tactics have motifs like skewer, pin, fork, weak back rank etc which can be used to guide you towards candidate moves. 

Are there similar positional motifs? 

I think Silman's imbalances is close to what I'm asking for, but is a bit too higher level and not especially useful in generating candidate moves. His concept of dream position is something to target in 10+ moves, and I find it hard to implement in practice. (Yes, major piece ending with his backward pawn is good for me, but we have 4 minors to trade, what's the first move?)

I'm looking for something less blue-sky and can give guidance for the next 1-2 moves. Example: h4-h5 against king side fiachetto; c4 is more powerful when opponent puts B on d6 (usually with opposing pawns in d4,d5). 

Of course, just as a pin does not always lead to winning a piece, these are ways to generate candidate moves and everything needs to be checked in a concrete position.

Also, are there any training software/website like chesstempo, but on positional puzzle? I tried chessimmo, but its positional puzzles are mostly opening moves (I only did the free ones though).
I found a very useful guide to thinking about both positional and tactical situations in an online course offered by VisualWize, who make chess visualization training software.  You can find it here.

You might find the portion of the course on positional evaluation helpful.

There are both sections of content and exercises to practice what you've learned. I have not tried their other training courses, which go into this material in more depth, but this course struck me as comprehensive and effective.

I admit to using an amalgam of different methods that I've learned from 
multiple sources, but this is the closest I can find to a comprehensive system.

You can also try a variety of chess training apps offered by ChessOK on the PC, and Chess King on Android (and probably Apple) - these are the same people, in two different markets.  On Android, their "Strategy" app offers a limited number of theoretical topics for free, plus a corresponding set of problems that cover Development, Space, Attack on the King, Attack on the Queenside, and Defense/Counterattack.  For a small charge (less than $10), you can buy the rest of the course, including 13 more topics in areas like: weak squares, positional sacrifices, hanging pawns, improving your pieces, pawn structure, open files and diagonals, etc.

Andrew Soltis wrote a good book on choosing a strategic move (well, any move) called How to Choose a Chess Move, in which he offered a short course in "priyomes", which are short plans to be used in certain types of positions to accomplish a short-term objective.  Unfortunately, there is no catalog of priyomes anywhere, since there 10's of thousands of them (apparently), but you get a good introduction to the concept.  Also, Mauricio Flores Rios' book, Chess Structures discusses quite a few openings, their tabiyas, and the types of plans each offers for both sides. That makes it a kind of catalog for priyomes for the openings.  These aren't software, but you can't always have everything...

Arthur Van De Oudeweetering has written an interesting book on 40 less well-known (but actually fairly frequently-occurring) priyomes that he has identified, which is called Improve Your Chess Pattern Recognition.  I'm working my way through that book, and adding the patterns to my pattern store, because they're surprisingly common (and effective).  He also does something I don't see often in chess training materials: he complements the normal "Do's" with some "Don'ts", pointing out some of the kinds of anomalies in the position that could render the pattern ineffective or even dangerous.

He has now published a sequel, called Train Your Chess Pattern Recognition.  I haven't seen this one, but I'd be surprised if it doesn't live up to the original. BTW: An Amazon reviewer has warned against buying the Kindle version of the 2nd book because the figurine characters don't render properly; the first book's Kindle edition is fine.