Place a small frying pan on a medium heat for 2 mins then toss the peanuts in. Toast them for 3-5 mins, shaking the pan often till they are golden all over. Tip on to a chopping board to cool.
While the peanuts cool, quarter the melon and scoop out the seeds. Slice away the skin, then chop each slice into 10-12 chunks. Put them in a large bowl.
Cut the cucumber in half widthways and pop 1 half in the fridge for another time (it’s just the thing for dunking in dips, or adding to smoothies or glasses of ice water). Halve the remaining cucumber half lengthways, then halve again. Chop into 1cm-thick pieces and add to the bowl with the melon.
Halve the chilli and flick out the seeds and white pith. Finely chop the chilli and place in a small bowl. Zest and juice in the lime.
Squeeze in the tamarind paste and the maple syrup. Stir well with a good pinch of salt.
Roughly chop the coriander leaves. Tear the basil leaves into small pieces. Chop the cooled peanuts.
Pour the tamarind dressing into the bowl with the cucumber and melon and toss together. Add most of the coriander and basil leaves and toss again.
Arrange the melon salad on a platter or 2 plates. Scatter over the remaining herbs and the toasted peanuts to serve.