You don't have to play every note in a chord.Sometimes playing just the most essential notes in a chord are enough.Sometimes even an essential note can be omitted in favor of a less essential note,it all depends on what all notes you are playing in combination.When only two notes are played they are called dyads or in more modern vernacular "double stops"...a familiar type of double stop is the power chord,consisting of just a root and a fifth.Power chords should be familiar to you as they are very common in rock and it's many subgenres.If you google around for the following terms you should find alot of info on the subject:"dyads","double stops","partial chords","jazz comping", "shell voicings",or "kernell voicings" or maybe even "skeleton voicings","freddy green style","funk chords","blues to jazz",etc.
here's some links to get you started in the right direction:
google some of the terms I mentioned it'll be worth it,and also check out guitarplayer.com's lessons
KEEP ON TRUCKIN'.....
In improvising within a modal context, a musician would basically start by thinking about playing the notes within that specific mode (e.g., D Dorian: D, E, F, G, A, B, C, D). - wikipedia "modal jazz" article
"In its most conventional sense, tonality refers to just the major and minor scale types - scales whose elements are capable of maintaining a consistent set of functional relationships." - A. Milne