Preheat oven to 250 degrees F and line 2 baking sheets with parchment paper.
In the bowl of a stand mixer with whisk attachment or in a large bowl with a hand mixer, beat egg whites and salt on medium-high speed until foamy. Add cream of tartar and continue to beat until soft peaks form, about 2 minutes.
Begin adding sugar, 1 Tbsp at a time. Keep beating until stiff peaks form, about 6-8 minutes.
Divide egg white mixture into 3 different bowls. In the first bowl, mix in lime zest and lime juice. In the second bowl, mix in orange zest and orange juice. In the third bowl, mix in raspberry extract.
Place a pastry bag fitted with a large round tip (I use Wilton 1A) in a tall drinking glass and fold over the top of the bag. Dip a pastry brush or paintbrush in the green food coloring and starting inside the pastry tip, brush a stroke of food coloring from the tip to the top of the bag. Repeat with orange food coloring and again with pink food coloring. Fill the bag with each of the flavors of meringue taking care to scoop each flavor on each side of the bag (rather than layering them) so that you'll get each flavor in each meringue you pipe out. Pipe mounds about 1 ½-inch in diameter onto prepared baking sheets.
Bake until meringues are dry and no longer glossy, about 1 hour. Turn off the oven, crack the door open a bit, and leave meringues in oven for another 2 hours to completely dry and avoid cracking.