So I can't tell if I have a defect in my phone, or I'm doing something wrong. I'll start zeroing in on a name I want to dial...then when I tap it with my finger, it doesn't do anything. If I hold my finger on it, I get a menu that let's me "edit the number" to dial as well as "view the contact", etc.....but just tapping it doesn't cause it to dial.
On my Eris, when I go through the steps you describe, and I tap quickly on a contact, it dials the "default number" for that contact. If I want to dial one of the many alternate (non-default) numbers associated with that contact, I have to long-press on that contact, select "View Contact". Then, each of the numbers has an entry - "Call Home", "Call Mobile", "Call Work", et cetera; a single tap on any of them dials that number.
In summary, that looks like
tap (Phone) -> keypad search -> long-press (Contact) -> tap (View Contact) -> tap (number).
Not including the initial tap and the keypad search, that's two taps and a long-press to dial any number in the contact database.
Here's an alternative that reduces to two taps total: put a shortcut on your home screen to Voice Dialer, tap it, say "Call Joe Shmoe {on mobile|at home|at work|at cell}, and then tap to confirm.
HTH
eu1
Edit: Oops, I see Caddyman already suggested the voice dial method


