Who wins this hand? Unique flush.?

A flush is 5 cards.  If the highest card in both flushes is the same, the 2nd highest card is the tiebreaker, and so on down the line.  A flush of A J 10 9 3 beats one of A J 10 9 2.

It is not possible to have a flush and a pair.  The flush requires all 5 cards of the same suit, and ofc there is only one of each number per suit.  

No doubt k6       

A flush is 5 cards.  If the highest card in both flushes is the same, the 2nd highest card is the tiebreaker, and so on down the line.  A flush of A J 10 9 3 beats one of A J 10 9 2.

It is not possible to have a flush and a pair.  The flush requires all 5 cards of the same suit, and ofc there is only one of each number per suit.  

LOL people keep asking this?

In Texas Hold 'em, as in most variants of poker, ALL hands consist of FIVE CARDS.  Each player makes the best hand they can using 5 of the seven cards available to them.

A flush is 5 cards.  All 5 cards are needed for the flush.  The highest card determines the winner, however if the highest card is the same (both aces, both Kings, whatever) then the second highest card determines the winner.  If the second highest card is also the same, then the third highest, and so on.  Only if all 5 cards of both flushes are the same denomination can the hands be tied.  This is quite rare, as it requires all 5 cards of the flush to be on the board, and neither player can have a card of that suit in their hand (unless their best hold card of that suit is lower than all 5 cards on the board).  All cards to a flush are ranked - there is no way two hole cards can contribute equally to a flush.

If a heart is needed to complete a flush, there is NO WAY two players can have an equal flush, since they can't possibly both have the same heart.

Straights are different.  If the board has 4 to a straight, there are 4 (or 8) cards in the deck that can complete that straight, and suits don't matter in a straight (unless it's a straight flush of course).  If a 10 is needed for a straight, up to 4 players could have that straight, since there are 4 10's in the deck, and suits don't matter.

But all hands are 5 cards, and the denominations of all 5 cards have a potential to make a difference.  The only time a card doesn't matter is if it's not one of your best 5 cards.

It's always based on best 5 cards of each player. In this case, both have a flush, so you go to the highest ranked card in the flush. In this case, that is also a tie with A, so you go to the next highest card in each flush. Here it becomes K vs. Q, so the one with the K wins.

The evaluation of the hands are as such...

Player A) Flush, A-K-Q-10-8 in Hearts

Player B) Flush, A-Q-10-8-4 in Hearts

The highest card is an Ace in both hands (being a community card).  Since all 5 cards are used in crafting the Flush, there's no cards available as kickers.

THEREFORE, this remains a tie & a SPLIT POT must be declared.

If you MUST nitpick the evaluations (going beyond what most casinos & tournament directors would declare), it would fall to the next highest card in their hands...  which would give Player A the advantage (& the pot) with their King vs Player B's Queen.

Keep in mind that in Texas Hold 'em (and other poker games) you use the available cards to make the best 5 card hand. There is no such thing as a 6 card flush because each player uses ONLY the 5 cards that make the best possible hand.

So player A's extra heart doesn't matter, they have a 5 card flush using the 5 highest hearts. Likewise player B's Ace doesn't help them because its not part of their 5 card flush.

When 2 or more players have a flush the tiebreaker is the highest card, If that's also tied the next tie breaker is the 2nd highest card, and you continue down to the 5th card if necessary. If all 5 cards were tied (which could only happen if the board has a flush) then its a split pot.

In this case Player A would win.

Player A has a flush with A,K,Q,10,8

Player B has a flush with A,Q.10,8,4

The first tiebreaker is high card - which is shared since they both have the Ace from the community cards.

The 2nd tiebreaker is the 2nd highest card: Player A has a king and player B is using the Queen from the community cards, king obviously beats queen, so Player A wins the hand and there's no need for any additional tiebreaker comparisons.

What you'll find is that with Texas hold 'em the player with the highest card in their hand (as part of the flush) will end up winning the hand. Even if the board has a flush (all 5 community cards are the same suit) a player can win if they have a card of the matching suit that is at least higher than the lowest card on the board.

If the top card is a tie, you look at the next highest card.  The player with the King wins.