In a medium saucepan over medium heat, add the oil and allow to warm 1 to 2 minutes. Then add the red onions and warm for 1 minute. Next, add the jalapenos and again warm for 1 minute. Then add the orange juice and vinegar, allowing the liquids to reduce and only coat the bottom of the pan, 2 to 3 minutes. Reduce the heat to low, stir in the jam and allow to warm for 2 minutes. Then remove from the heat and cool for 5 minutes.
In a medium bowl, whisk together the lemon juice, sambal, pineapple and sugar. Then add the watermelon, strawberries, kiwi, cilantro and mint. Toss together and finish with lemon juice mixture. Stir.
Allow this to rest for 20 to 30 minutes, ensuring flavors have blended.