The difference between a tactical or a strategic/positional move lies in its justification. Almost all good moves have a positional and a tactical justification, otherwise they may be tactical or positional mistakes. The exception, of course, are moves that lead to mate or a big material advantage, those could probably be called purely tactical moves.
Which justification is more important to you depends on your abilities and your style. If the tactical justification of a move is obvious to you, it might seem like a purely positional move. On the other hand if a move has a deep strategic idea, but requires complicated calculation, you may regard it as a tactical move. I'll give you an example:
[Title "White to move"]
[fen "rnb1kb1r/pp3ppp/2p1q3/4P2n/4Np2/5N2/PPP1Q1PP/R1B1KB1R w KQkq - 1 10"]
1.g4 Qxg4 2.Rg1 Qe6 3.Rg5 g6 4.Rxh5
g4 may strike you as a very tactical move: It is a pawn sacrifice and its justification involves a lot of calculation including an exchange sacrifice. But the final goal is really very strategic: Conquering the dark squares, especially f6 and f4. White is winning.
Incidentally this is the big difference between computer chess and human chess: For a computer every move is a tactical move. Every move is justified by the calculation of variations. For humans this is a gradual thing and if you are looking for purely tactical moves you should focus on combinations with a very clear result.
If you want only a crude distinction I would propose to let an engine calculate a few moves: If a move is only viable after a certain search depth, you can call it tactical. Every move viable even at very low ply would be strategic/positional.