Prepare the ginger simple syrup: In a small pot, combine the water, sugar and ginger. Bring to a boil and simmer for 3 minutes until the sugar is dissolved. Remove from the heat, cover and steep for 5 minutes. Strain. Stir in the lime juice. Set aside.
Prepare the lime salt: Mix the lime zest with salt together in a small cup or bowl. Rub the zest into the salt until completely mixed.
Prepare the watermelon and toppings: With the tip of a paring knife, make an outline on the top of one watermelon slice that is 1/4-inch from the edge and 1/4-inch deep. Make a pocket in the slice by sticking the knife in the side of the slice 1/4-inch deep. Lift out the cut piece on top of the slice. Enjoy the cut piece as a chef’s snack or save for another use. Repeat with the remaining watermelon slices. The prepared watermelon slices are now watermelon plates.
Using a skewer, poke 6 to 8 holes halfway through each watermelon plate. Set aside.
Prepare the strawberry-peach topping: Combine the strawberries, peaches and about 2 tablespoons of the ginger simple syrup in a medium bowl. Add the basil and gently toss.
Prepare the radish topping: Combine the radishes, red onions, jalapeno, olive oil and vinegar in a medium bowl. Season with salt and pepper. Add the mint and gently toss.
Sprinkle the watermelon plates with the lime salt. Top half of the watermelon plates with the strawberry mixture. Top the remaining half of the watermelon plates with the radish mixture.
The remaining ginger simple syrup is delicious in cocktails.