Well, bonjour is the easy one-- that just means hello. But let's see . . . if you really wanted to say hi to a friend, you could say Ça va?

That's a pretty casual way of asking how somebody is. And then you could reply ça va bien, it's going good.

[A beat, and then:]

. . . hey. Uh. About before . . . did you see anything weird about me?