"Is that OK [with/to] you?"
Solution 1:
The idiom for "to" is "Does that seem ok to you?" or "Does that look ok to you?" The first is a query about the general propriety of something:
They fired him with no notice. Does that seem ok to you?
The second may be used to ask about an uncertainty the speaker has about correct usage:
On the second line, the word canceled is spelled with one "l"; does that look ok to you?
"Is that ok with you?" asks whether you have any objections to a situation or a proposal:
We're going to delay the board meeting until next week. Is that ok with you?